diff --git a/tests/common.py b/tests/common.py
index bdebc7217a7..55878f76da7 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -282,7 +282,7 @@ async def async_test_home_assistant(loop, load_registries=True):
     hass.config.latitude = 32.87336
     hass.config.longitude = -117.22743
     hass.config.elevation = 0
-    hass.config.time_zone = "US/Pacific"
+    hass.config.set_time_zone("US/Pacific")
     hass.config.units = METRIC_SYSTEM
     hass.config.media_dirs = {"local": get_test_config_dir("media")}
     hass.config.skip_pip = True
diff --git a/tests/components/aemet/test_sensor.py b/tests/components/aemet/test_sensor.py
index 7887139a386..b5e7679dbe6 100644
--- a/tests/components/aemet/test_sensor.py
+++ b/tests/components/aemet/test_sensor.py
@@ -15,6 +15,7 @@ from .util import async_init_integration
 async def test_aemet_forecast_create_sensors(hass):
     """Test creation of forecast sensors."""
 
+    hass.config.set_time_zone("UTC")
     now = dt_util.parse_datetime("2021-01-09 12:00:00+00:00")
     with patch("homeassistant.util.dt.now", return_value=now), patch(
         "homeassistant.util.dt.utcnow", return_value=now
diff --git a/tests/components/aemet/test_weather.py b/tests/components/aemet/test_weather.py
index 43acf4c1c87..d1f1889c807 100644
--- a/tests/components/aemet/test_weather.py
+++ b/tests/components/aemet/test_weather.py
@@ -30,6 +30,7 @@ from .util import async_init_integration
 async def test_aemet_weather(hass):
     """Test states of the weather."""
 
+    hass.config.set_time_zone("UTC")
     now = dt_util.parse_datetime("2021-01-09 12:00:00+00:00")
     with patch("homeassistant.util.dt.now", return_value=now), patch(
         "homeassistant.util.dt.utcnow", return_value=now
diff --git a/tests/components/caldav/test_calendar.py b/tests/components/caldav/test_calendar.py
index 6993aa97081..7bfb8b620f6 100644
--- a/tests/components/caldav/test_calendar.py
+++ b/tests/components/caldav/test_calendar.py
@@ -222,15 +222,6 @@ CALDAV_CONFIG = {
     "custom_calendars": [],
 }
 
-ORIG_TZ = dt.DEFAULT_TIME_ZONE
-
-
-@pytest.fixture(autouse=True)
-def reset_tz():
-    """Restore the default TZ after test runs."""
-    yield
-    dt.DEFAULT_TIME_ZONE = ORIG_TZ
-
 
 @pytest.fixture
 def set_tz(request):
@@ -239,21 +230,21 @@ def set_tz(request):
 
 
 @pytest.fixture
-def utc():
+def utc(hass):
     """Set the default TZ to UTC."""
-    dt.set_default_time_zone(dt.get_time_zone("UTC"))
+    hass.config.set_time_zone("UTC")
 
 
 @pytest.fixture
-def new_york():
+def new_york(hass):
     """Set the default TZ to America/New_York."""
-    dt.set_default_time_zone(dt.get_time_zone("America/New_York"))
+    hass.config.set_time_zone("America/New_York")
 
 
 @pytest.fixture
-def baghdad():
+def baghdad(hass):
     """Set the default TZ to Asia/Baghdad."""
-    dt.set_default_time_zone(dt.get_time_zone("Asia/Baghdad"))
+    hass.config.set_time_zone("Asia/Baghdad")
 
 
 @pytest.fixture(autouse=True)
@@ -364,8 +355,9 @@ async def test_setup_component_with_one_custom_calendar(hass, mock_dav_client):
     assert state.name == "HomeOffice"
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(17, 45))
-async def test_ongoing_event(mock_now, hass, calendar):
+async def test_ongoing_event(mock_now, hass, calendar, set_tz):
     """Test that the ongoing event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -385,8 +377,9 @@ async def test_ongoing_event(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(17, 30))
-async def test_just_ended_event(mock_now, hass, calendar):
+async def test_just_ended_event(mock_now, hass, calendar, set_tz):
     """Test that the next ongoing event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -406,8 +399,9 @@ async def test_just_ended_event(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(17, 00))
-async def test_ongoing_event_different_tz(mock_now, hass, calendar):
+async def test_ongoing_event_different_tz(mock_now, hass, calendar, set_tz):
     """Test that the ongoing event with another timezone is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -427,8 +421,9 @@ async def test_ongoing_event_different_tz(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(19, 10))
-async def test_ongoing_floating_event_returned(mock_now, hass, calendar):
+async def test_ongoing_floating_event_returned(mock_now, hass, calendar, set_tz):
     """Test that floating events without timezones work."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -448,8 +443,9 @@ async def test_ongoing_floating_event_returned(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(8, 30))
-async def test_ongoing_event_with_offset(mock_now, hass, calendar):
+async def test_ongoing_event_with_offset(mock_now, hass, calendar, set_tz):
     """Test that the offset is taken into account."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -469,8 +465,9 @@ async def test_ongoing_event_with_offset(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(12, 00))
-async def test_matching_filter(mock_now, hass, calendar):
+async def test_matching_filter(mock_now, hass, calendar, set_tz):
     """Test that the matching event is returned."""
     config = dict(CALDAV_CONFIG)
     config["custom_calendars"] = [
@@ -495,8 +492,9 @@ async def test_matching_filter(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(12, 00))
-async def test_matching_filter_real_regexp(mock_now, hass, calendar):
+async def test_matching_filter_real_regexp(mock_now, hass, calendar, set_tz):
     """Test that the event matching the regexp is returned."""
     config = dict(CALDAV_CONFIG)
     config["custom_calendars"] = [
@@ -625,8 +623,9 @@ async def test_all_day_event_returned_late(hass, calendar, set_tz):
     )
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(21, 45))
-async def test_event_rrule(mock_now, hass, calendar):
+async def test_event_rrule(mock_now, hass, calendar, set_tz):
     """Test that the future recurring event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -646,8 +645,9 @@ async def test_event_rrule(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(22, 15))
-async def test_event_rrule_ongoing(mock_now, hass, calendar):
+async def test_event_rrule_ongoing(mock_now, hass, calendar, set_tz):
     """Test that the current recurring event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -667,8 +667,9 @@ async def test_event_rrule_ongoing(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(22, 45))
-async def test_event_rrule_duration(mock_now, hass, calendar):
+async def test_event_rrule_duration(mock_now, hass, calendar, set_tz):
     """Test that the future recurring event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -688,8 +689,9 @@ async def test_event_rrule_duration(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(23, 15))
-async def test_event_rrule_duration_ongoing(mock_now, hass, calendar):
+async def test_event_rrule_duration_ongoing(mock_now, hass, calendar, set_tz):
     """Test that the ongoing recurring event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -709,8 +711,9 @@ async def test_event_rrule_duration_ongoing(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch("homeassistant.util.dt.now", return_value=_local_datetime(23, 37))
-async def test_event_rrule_endless(mock_now, hass, calendar):
+async def test_event_rrule_endless(mock_now, hass, calendar, set_tz):
     """Test that the endless recurring event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -798,11 +801,12 @@ async def test_event_rrule_all_day_late(hass, calendar, set_tz):
     )
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch(
     "homeassistant.util.dt.now",
     return_value=dt.as_local(datetime.datetime(2015, 11, 27, 0, 15)),
 )
-async def test_event_rrule_hourly_on_first(mock_now, hass, calendar):
+async def test_event_rrule_hourly_on_first(mock_now, hass, calendar, set_tz):
     """Test that the endless recurring event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
@@ -822,11 +826,12 @@ async def test_event_rrule_hourly_on_first(mock_now, hass, calendar):
     }
 
 
+@pytest.mark.parametrize("set_tz", ["utc"], indirect=True)
 @patch(
     "homeassistant.util.dt.now",
     return_value=dt.as_local(datetime.datetime(2015, 11, 27, 11, 15)),
 )
-async def test_event_rrule_hourly_on_last(mock_now, hass, calendar):
+async def test_event_rrule_hourly_on_last(mock_now, hass, calendar, set_tz):
     """Test that the endless recurring event is returned."""
     assert await async_setup_component(hass, "calendar", {"calendar": CALDAV_CONFIG})
     await hass.async_block_till_done()
diff --git a/tests/components/climacell/test_weather.py b/tests/components/climacell/test_weather.py
index 3bac69dcbc5..d5385b6cfd5 100644
--- a/tests/components/climacell/test_weather.py
+++ b/tests/components/climacell/test_weather.py
@@ -91,7 +91,7 @@ async def test_v3_weather(
     assert weather_state.attributes[ATTR_FORECAST] == [
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_SUNNY,
-            ATTR_FORECAST_TIME: "2021-03-07T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-07T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 0,
             ATTR_FORECAST_TEMP: 7,
@@ -99,7 +99,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-08T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-08T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 0,
             ATTR_FORECAST_TEMP: 10,
@@ -107,7 +107,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-09T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-09T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 0,
             ATTR_FORECAST_TEMP: 19,
@@ -115,7 +115,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-10T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-10T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 0,
             ATTR_FORECAST_TEMP: 18,
@@ -123,7 +123,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-11T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-11T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 5,
             ATTR_FORECAST_TEMP: 20,
@@ -131,7 +131,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-12T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-12T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 0.0457,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 25,
             ATTR_FORECAST_TEMP: 20,
@@ -139,7 +139,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-13T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-13T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 25,
             ATTR_FORECAST_TEMP: 16,
@@ -147,7 +147,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_RAINY,
-            ATTR_FORECAST_TIME: "2021-03-14T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-14T00:00:00-08:00",
             ATTR_FORECAST_PRECIPITATION: 1.0744,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 75,
             ATTR_FORECAST_TEMP: 6,
@@ -155,7 +155,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_SNOWY,
-            ATTR_FORECAST_TIME: "2021-03-15T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-15T00:00:00-07:00",  # DST starts
             ATTR_FORECAST_PRECIPITATION: 7.3050,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 95,
             ATTR_FORECAST_TEMP: 1,
@@ -163,7 +163,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-16T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-16T00:00:00-07:00",
             ATTR_FORECAST_PRECIPITATION: 0.0051,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 5,
             ATTR_FORECAST_TEMP: 6,
@@ -171,7 +171,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-17T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-17T00:00:00-07:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 0,
             ATTR_FORECAST_TEMP: 11,
@@ -179,7 +179,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-18T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-18T00:00:00-07:00",
             ATTR_FORECAST_PRECIPITATION: 0,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 5,
             ATTR_FORECAST_TEMP: 12,
@@ -187,7 +187,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-19T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-19T00:00:00-07:00",
             ATTR_FORECAST_PRECIPITATION: 0.1778,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 45,
             ATTR_FORECAST_TEMP: 9,
@@ -195,7 +195,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_RAINY,
-            ATTR_FORECAST_TIME: "2021-03-20T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-20T00:00:00-07:00",
             ATTR_FORECAST_PRECIPITATION: 1.2319,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 55,
             ATTR_FORECAST_TEMP: 5,
@@ -203,7 +203,7 @@ async def test_v3_weather(
         },
         {
             ATTR_FORECAST_CONDITION: ATTR_CONDITION_CLOUDY,
-            ATTR_FORECAST_TIME: "2021-03-21T00:00:00+00:00",
+            ATTR_FORECAST_TIME: "2021-03-21T00:00:00-07:00",
             ATTR_FORECAST_PRECIPITATION: 0.0432,
             ATTR_FORECAST_PRECIPITATION_PROBABILITY: 20,
             ATTR_FORECAST_TEMP: 7,
diff --git a/tests/components/config/test_core.py b/tests/components/config/test_core.py
index b78ed50cdf2..33309f6b6c6 100644
--- a/tests/components/config/test_core.py
+++ b/tests/components/config/test_core.py
@@ -10,8 +10,6 @@ from homeassistant.components.websocket_api.const import TYPE_RESULT
 from homeassistant.const import CONF_UNIT_SYSTEM, CONF_UNIT_SYSTEM_IMPERIAL
 from homeassistant.util import dt as dt_util, location
 
-ORIG_TIME_ZONE = dt_util.DEFAULT_TIME_ZONE
-
 
 @pytest.fixture
 async def client(hass, hass_ws_client):
diff --git a/tests/components/flux/test_switch.py b/tests/components/flux/test_switch.py
index 275c10c5592..19d5c064e82 100644
--- a/tests/components/flux/test_switch.py
+++ b/tests/components/flux/test_switch.py
@@ -23,6 +23,12 @@ from tests.common import (
 )
 
 
+@pytest.fixture(autouse=True)
+def set_utc(hass):
+    """Set timezone to UTC."""
+    hass.config.set_time_zone("UTC")
+
+
 async def test_valid_config(hass):
     """Test configuration."""
     assert await async_setup_component(
diff --git a/tests/components/forecast_solar/conftest.py b/tests/components/forecast_solar/conftest.py
index 6e1adc14b7f..408c5423861 100644
--- a/tests/components/forecast_solar/conftest.py
+++ b/tests/components/forecast_solar/conftest.py
@@ -43,8 +43,11 @@ def mock_config_entry() -> MockConfigEntry:
 
 
 @pytest.fixture
-def mock_forecast_solar() -> Generator[None, MagicMock, None]:
-    """Return a mocked Forecast.Solar client."""
+def mock_forecast_solar(hass) -> Generator[None, MagicMock, None]:
+    """Return a mocked Forecast.Solar client.
+
+    hass fixture included because it sets the time zone.
+    """
     with patch(
         "homeassistant.components.forecast_solar.ForecastSolar", autospec=True
     ) as forecast_solar_mock:
diff --git a/tests/components/forecast_solar/test_sensor.py b/tests/components/forecast_solar/test_sensor.py
index ee8afe5794b..a05acb5bc16 100644
--- a/tests/components/forecast_solar/test_sensor.py
+++ b/tests/components/forecast_solar/test_sensor.py
@@ -68,7 +68,7 @@ async def test_sensors(
     assert entry
     assert state
     assert entry.unique_id == f"{entry_id}_power_highest_peak_time_today"
-    assert state.state == "2021-06-27T13:00:00+00:00"
+    assert state.state == "2021-06-27T20:00:00+00:00"  # Timestamp sensor is UTC
     assert state.attributes.get(ATTR_FRIENDLY_NAME) == "Highest Power Peak Time - Today"
     assert state.attributes.get(ATTR_STATE_CLASS) is None
     assert state.attributes.get(ATTR_DEVICE_CLASS) == SensorDeviceClass.TIMESTAMP
@@ -80,7 +80,7 @@ async def test_sensors(
     assert entry
     assert state
     assert entry.unique_id == f"{entry_id}_power_highest_peak_time_tomorrow"
-    assert state.state == "2021-06-27T14:00:00+00:00"
+    assert state.state == "2021-06-27T21:00:00+00:00"  # Timestamp sensor is UTC
     assert (
         state.attributes.get(ATTR_FRIENDLY_NAME) == "Highest Power Peak Time - Tomorrow"
     )
diff --git a/tests/components/google/conftest.py b/tests/components/google/conftest.py
index c3b8ae4e172..102b8a1ccc6 100644
--- a/tests/components/google/conftest.py
+++ b/tests/components/google/conftest.py
@@ -15,13 +15,10 @@ from homeassistant.components.google import CONF_TRACK_NEW, DOMAIN
 from homeassistant.const import CONF_CLIENT_ID, CONF_CLIENT_SECRET
 from homeassistant.core import HomeAssistant
 from homeassistant.setup import async_setup_component
-import homeassistant.util.dt as dt_util
 from homeassistant.util.dt import utcnow
 
 from tests.common import MockConfigEntry
 
-ORIG_TIMEZONE = dt_util.DEFAULT_TIME_ZONE
-
 ApiResult = Callable[[dict[str, Any]], None]
 ComponentSetup = Callable[[], Awaitable[bool]]
 _T = TypeVar("_T")
@@ -252,10 +249,7 @@ def set_time_zone(hass):
     """Set the time zone for the tests."""
     # Set our timezone to CST/Regina so we can check calculations
     # This keeps UTC-6 all year round
-    hass.config.time_zone = "CST"
-    dt_util.set_default_time_zone(dt_util.get_time_zone("America/Regina"))
-    yield
-    dt_util.set_default_time_zone(ORIG_TIMEZONE)
+    hass.config.set_time_zone("America/Regina")
 
 
 @pytest.fixture
diff --git a/tests/components/google/test_init.py b/tests/components/google/test_init.py
index 6fc575ba03d..49e10d137b6 100644
--- a/tests/components/google/test_init.py
+++ b/tests/components/google/test_init.py
@@ -417,11 +417,11 @@ async def test_add_event_date_time(
             "description": "Description",
             "start": {
                 "dateTime": start_datetime.isoformat(timespec="seconds"),
-                "timeZone": "CST",
+                "timeZone": "America/Regina",
             },
             "end": {
                 "dateTime": end_datetime.isoformat(timespec="seconds"),
-                "timeZone": "CST",
+                "timeZone": "America/Regina",
             },
         },
     )
diff --git a/tests/components/input_datetime/test_init.py b/tests/components/input_datetime/test_init.py
index 0a968caf67f..28ca2ab02bd 100644
--- a/tests/components/input_datetime/test_init.py
+++ b/tests/components/input_datetime/test_init.py
@@ -38,8 +38,6 @@ INITIAL_DATE = "2020-01-10"
 INITIAL_TIME = "23:45:56"
 INITIAL_DATETIME = f"{INITIAL_DATE} {INITIAL_TIME}"
 
-ORIG_TIMEZONE = dt_util.DEFAULT_TIME_ZONE
-
 
 @pytest.fixture
 def storage_setup(hass, hass_storage):
@@ -131,7 +129,9 @@ async def test_set_datetime(hass):
 
     entity_id = "input_datetime.test_datetime"
 
-    dt_obj = datetime.datetime(2017, 9, 7, 19, 46, 30, tzinfo=datetime.timezone.utc)
+    dt_obj = datetime.datetime(
+        2017, 9, 7, 19, 46, 30, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
 
     await async_set_date_and_time(hass, entity_id, dt_obj)
 
@@ -157,7 +157,9 @@ async def test_set_datetime_2(hass):
 
     entity_id = "input_datetime.test_datetime"
 
-    dt_obj = datetime.datetime(2017, 9, 7, 19, 46, 30, tzinfo=datetime.timezone.utc)
+    dt_obj = datetime.datetime(
+        2017, 9, 7, 19, 46, 30, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
 
     await async_set_datetime(hass, entity_id, dt_obj)
 
@@ -183,7 +185,9 @@ async def test_set_datetime_3(hass):
 
     entity_id = "input_datetime.test_datetime"
 
-    dt_obj = datetime.datetime(2017, 9, 7, 19, 46, 30, tzinfo=datetime.timezone.utc)
+    dt_obj = datetime.datetime(
+        2017, 9, 7, 19, 46, 30, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
 
     await async_set_timestamp(hass, entity_id, dt_util.as_utc(dt_obj).timestamp())
 
@@ -649,101 +653,97 @@ async def test_setup_no_config(hass, hass_admin_user):
 
 async def test_timestamp(hass):
     """Test timestamp."""
-    try:
-        dt_util.set_default_time_zone(dt_util.get_time_zone("America/Los_Angeles"))
+    hass.config.set_time_zone("America/Los_Angeles")
 
-        assert await async_setup_component(
-            hass,
-            DOMAIN,
-            {
-                DOMAIN: {
-                    "test_datetime_initial_with_tz": {
-                        "has_time": True,
-                        "has_date": True,
-                        "initial": "2020-12-13 10:00:00+01:00",
-                    },
-                    "test_datetime_initial_without_tz": {
-                        "has_time": True,
-                        "has_date": True,
-                        "initial": "2020-12-13 10:00:00",
-                    },
-                    "test_time_initial": {
-                        "has_time": True,
-                        "has_date": False,
-                        "initial": "10:00:00",
-                    },
-                }
-            },
-        )
+    assert await async_setup_component(
+        hass,
+        DOMAIN,
+        {
+            DOMAIN: {
+                "test_datetime_initial_with_tz": {
+                    "has_time": True,
+                    "has_date": True,
+                    "initial": "2020-12-13 10:00:00+01:00",
+                },
+                "test_datetime_initial_without_tz": {
+                    "has_time": True,
+                    "has_date": True,
+                    "initial": "2020-12-13 10:00:00",
+                },
+                "test_time_initial": {
+                    "has_time": True,
+                    "has_date": False,
+                    "initial": "10:00:00",
+                },
+            }
+        },
+    )
 
-        # initial has been converted to the set timezone
-        state_with_tz = hass.states.get("input_datetime.test_datetime_initial_with_tz")
-        assert state_with_tz is not None
-        # Timezone LA is UTC-8 => timestamp carries +01:00 => delta is -9 => 10:00 - 09:00 => 01:00
-        assert state_with_tz.state == "2020-12-13 01:00:00"
-        assert (
-            dt_util.as_local(
-                dt_util.utc_from_timestamp(state_with_tz.attributes[ATTR_TIMESTAMP])
-            ).strftime(FMT_DATETIME)
-            == "2020-12-13 01:00:00"
-        )
+    # initial has been converted to the set timezone
+    state_with_tz = hass.states.get("input_datetime.test_datetime_initial_with_tz")
+    assert state_with_tz is not None
+    # Timezone LA is UTC-8 => timestamp carries +01:00 => delta is -9 => 10:00 - 09:00 => 01:00
+    assert state_with_tz.state == "2020-12-13 01:00:00"
+    assert (
+        dt_util.as_local(
+            dt_util.utc_from_timestamp(state_with_tz.attributes[ATTR_TIMESTAMP])
+        ).strftime(FMT_DATETIME)
+        == "2020-12-13 01:00:00"
+    )
 
-        # initial has been interpreted as being part of set timezone
-        state_without_tz = hass.states.get(
-            "input_datetime.test_datetime_initial_without_tz"
-        )
-        assert state_without_tz is not None
-        assert state_without_tz.state == "2020-12-13 10:00:00"
-        # Timezone LA is UTC-8 => timestamp has no zone (= assumed local) => delta to UTC is +8 => 10:00 + 08:00 => 18:00
-        assert (
-            dt_util.utc_from_timestamp(
-                state_without_tz.attributes[ATTR_TIMESTAMP]
-            ).strftime(FMT_DATETIME)
-            == "2020-12-13 18:00:00"
-        )
-        assert (
-            dt_util.as_local(
-                dt_util.utc_from_timestamp(state_without_tz.attributes[ATTR_TIMESTAMP])
-            ).strftime(FMT_DATETIME)
-            == "2020-12-13 10:00:00"
-        )
-        # Use datetime.datetime.fromtimestamp
-        assert (
-            dt_util.as_local(
-                datetime.datetime.fromtimestamp(
-                    state_without_tz.attributes[ATTR_TIMESTAMP], datetime.timezone.utc
-                )
-            ).strftime(FMT_DATETIME)
-            == "2020-12-13 10:00:00"
-        )
+    # initial has been interpreted as being part of set timezone
+    state_without_tz = hass.states.get(
+        "input_datetime.test_datetime_initial_without_tz"
+    )
+    assert state_without_tz is not None
+    assert state_without_tz.state == "2020-12-13 10:00:00"
+    # Timezone LA is UTC-8 => timestamp has no zone (= assumed local) => delta to UTC is +8 => 10:00 + 08:00 => 18:00
+    assert (
+        dt_util.utc_from_timestamp(
+            state_without_tz.attributes[ATTR_TIMESTAMP]
+        ).strftime(FMT_DATETIME)
+        == "2020-12-13 18:00:00"
+    )
+    assert (
+        dt_util.as_local(
+            dt_util.utc_from_timestamp(state_without_tz.attributes[ATTR_TIMESTAMP])
+        ).strftime(FMT_DATETIME)
+        == "2020-12-13 10:00:00"
+    )
+    # Use datetime.datetime.fromtimestamp
+    assert (
+        dt_util.as_local(
+            datetime.datetime.fromtimestamp(
+                state_without_tz.attributes[ATTR_TIMESTAMP], datetime.timezone.utc
+            )
+        ).strftime(FMT_DATETIME)
+        == "2020-12-13 10:00:00"
+    )
 
-        # Test initial time sets timestamp correctly.
-        state_time = hass.states.get("input_datetime.test_time_initial")
-        assert state_time is not None
-        assert state_time.state == "10:00:00"
-        assert state_time.attributes[ATTR_TIMESTAMP] == 10 * 60 * 60
+    # Test initial time sets timestamp correctly.
+    state_time = hass.states.get("input_datetime.test_time_initial")
+    assert state_time is not None
+    assert state_time.state == "10:00:00"
+    assert state_time.attributes[ATTR_TIMESTAMP] == 10 * 60 * 60
 
-        # Test that setting the timestamp of an entity works.
-        await hass.services.async_call(
-            DOMAIN,
-            "set_datetime",
-            {
-                ATTR_ENTITY_ID: "input_datetime.test_datetime_initial_with_tz",
-                ATTR_TIMESTAMP: state_without_tz.attributes[ATTR_TIMESTAMP],
-            },
-            blocking=True,
-        )
-        state_with_tz_updated = hass.states.get(
-            "input_datetime.test_datetime_initial_with_tz"
-        )
-        assert state_with_tz_updated.state == "2020-12-13 10:00:00"
-        assert (
-            state_with_tz_updated.attributes[ATTR_TIMESTAMP]
-            == state_without_tz.attributes[ATTR_TIMESTAMP]
-        )
-
-    finally:
-        dt_util.set_default_time_zone(ORIG_TIMEZONE)
+    # Test that setting the timestamp of an entity works.
+    await hass.services.async_call(
+        DOMAIN,
+        "set_datetime",
+        {
+            ATTR_ENTITY_ID: "input_datetime.test_datetime_initial_with_tz",
+            ATTR_TIMESTAMP: state_without_tz.attributes[ATTR_TIMESTAMP],
+        },
+        blocking=True,
+    )
+    state_with_tz_updated = hass.states.get(
+        "input_datetime.test_datetime_initial_with_tz"
+    )
+    assert state_with_tz_updated.state == "2020-12-13 10:00:00"
+    assert (
+        state_with_tz_updated.attributes[ATTR_TIMESTAMP]
+        == state_without_tz.attributes[ATTR_TIMESTAMP]
+    )
 
 
 @pytest.mark.parametrize(
diff --git a/tests/components/jewish_calendar/__init__.py b/tests/components/jewish_calendar/__init__.py
index b0279fd2748..fbcd6c5325f 100644
--- a/tests/components/jewish_calendar/__init__.py
+++ b/tests/components/jewish_calendar/__init__.py
@@ -13,13 +13,6 @@ HDATE_DEFAULT_ALTITUDE = 754
 NYC_LATLNG = _LatLng(40.7128, -74.0060)
 JERUSALEM_LATLNG = _LatLng(31.778, 35.235)
 
-ORIG_TIME_ZONE = dt_util.DEFAULT_TIME_ZONE
-
-
-def teardown_module():
-    """Reset time zone."""
-    dt_util.set_default_time_zone(ORIG_TIME_ZONE)
-
 
 def make_nyc_test_params(dtime, results, havdalah_offset=0):
     """Make test params for NYC."""
diff --git a/tests/components/jewish_calendar/test_binary_sensor.py b/tests/components/jewish_calendar/test_binary_sensor.py
index b34dfdb28e4..15052243baa 100644
--- a/tests/components/jewish_calendar/test_binary_sensor.py
+++ b/tests/components/jewish_calendar/test_binary_sensor.py
@@ -181,7 +181,7 @@ async def test_issur_melacha_sensor(
     time_zone = dt_util.get_time_zone(tzname)
     test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = tzname
+    hass.config.set_time_zone(tzname)
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 
@@ -272,7 +272,7 @@ async def test_issur_melacha_sensor_update(
     time_zone = dt_util.get_time_zone(tzname)
     test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = tzname
+    hass.config.set_time_zone(tzname)
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 
diff --git a/tests/components/jewish_calendar/test_sensor.py b/tests/components/jewish_calendar/test_sensor.py
index 879b5edb120..e2d24bcef04 100644
--- a/tests/components/jewish_calendar/test_sensor.py
+++ b/tests/components/jewish_calendar/test_sensor.py
@@ -165,7 +165,7 @@ async def test_jewish_calendar_sensor(
     time_zone = dt_util.get_time_zone(tzname)
     test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = tzname
+    hass.config.set_time_zone(tzname)
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 
@@ -510,7 +510,7 @@ async def test_shabbat_times_sensor(
     time_zone = dt_util.get_time_zone(tzname)
     test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = tzname
+    hass.config.set_time_zone(tzname)
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 
diff --git a/tests/components/pvpc_hourly_pricing/test_config_flow.py b/tests/components/pvpc_hourly_pricing/test_config_flow.py
index ba0dc802007..4a9530768a6 100644
--- a/tests/components/pvpc_hourly_pricing/test_config_flow.py
+++ b/tests/components/pvpc_hourly_pricing/test_config_flow.py
@@ -12,7 +12,6 @@ from homeassistant.components.pvpc_hourly_pricing import (
 )
 from homeassistant.const import CONF_NAME
 from homeassistant.helpers import entity_registry as er
-from homeassistant.util import dt as dt_util
 
 from .conftest import check_valid_state
 
@@ -32,7 +31,7 @@ async def test_config_flow(
     - Check removal and add again to check state restoration
     - Configure options to change power and tariff to "2.0TD"
     """
-    hass.config.time_zone = dt_util.get_time_zone("Europe/Madrid")
+    hass.config.set_time_zone("Europe/Madrid")
     tst_config = {
         CONF_NAME: "test",
         ATTR_TARIFF: TARIFFS[1],
diff --git a/tests/components/pvpc_hourly_pricing/test_sensor.py b/tests/components/pvpc_hourly_pricing/test_sensor.py
index 727a144e75d..bbea27477cf 100644
--- a/tests/components/pvpc_hourly_pricing/test_sensor.py
+++ b/tests/components/pvpc_hourly_pricing/test_sensor.py
@@ -11,7 +11,6 @@ from homeassistant.components.pvpc_hourly_pricing import (
     TARIFFS,
 )
 from homeassistant.const import CONF_NAME
-from homeassistant.util import dt as dt_util
 
 from .conftest import check_valid_state
 
@@ -29,7 +28,7 @@ async def test_multi_sensor_migration(
 ):
     """Test tariff migration when there are >1 old sensors."""
     entity_reg = mock_registry(hass)
-    hass.config.time_zone = dt_util.get_time_zone("Europe/Madrid")
+    hass.config.set_time_zone("Europe/Madrid")
     uid_1 = "discrimination"
     uid_2 = "normal"
     old_conf_1 = {CONF_NAME: "test_pvpc_1", ATTR_TARIFF: uid_1}
diff --git a/tests/components/recorder/test_statistics.py b/tests/components/recorder/test_statistics.py
index c96465a671f..fe05dbc25ab 100644
--- a/tests/components/recorder/test_statistics.py
+++ b/tests/components/recorder/test_statistics.py
@@ -37,6 +37,8 @@ import homeassistant.util.dt as dt_util
 from tests.common import get_test_home_assistant, mock_registry
 from tests.components.recorder.common import wait_recording_done
 
+ORIG_TZ = dt_util.DEFAULT_TIME_ZONE
+
 
 def test_compile_hourly_statistics(hass_recorder):
     """Test compiling hourly statistics."""
@@ -841,6 +843,7 @@ def test_delete_duplicates(caplog, tmpdir):
                 session.add(recorder.models.Statistics.from_stats(3, stat))
 
         hass.stop()
+        dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     # Test that the duplicates are removed during migration from schema 23
     hass = get_test_home_assistant()
@@ -849,6 +852,7 @@ def test_delete_duplicates(caplog, tmpdir):
     wait_recording_done(hass)
     wait_recording_done(hass)
     hass.stop()
+    dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     assert "Deleted 2 duplicated statistics rows" in caplog.text
     assert "Found non identical" not in caplog.text
@@ -1014,6 +1018,7 @@ def test_delete_duplicates_many(caplog, tmpdir):
                 session.add(recorder.models.Statistics.from_stats(3, stat))
 
         hass.stop()
+        dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     # Test that the duplicates are removed during migration from schema 23
     hass = get_test_home_assistant()
@@ -1022,6 +1027,7 @@ def test_delete_duplicates_many(caplog, tmpdir):
     wait_recording_done(hass)
     wait_recording_done(hass)
     hass.stop()
+    dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     assert "Deleted 3002 duplicated statistics rows" in caplog.text
     assert "Found non identical" not in caplog.text
@@ -1149,6 +1155,7 @@ def test_delete_duplicates_non_identical(caplog, tmpdir):
                 session.add(recorder.models.Statistics.from_stats(2, stat))
 
         hass.stop()
+        dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     # Test that the duplicates are removed during migration from schema 23
     hass = get_test_home_assistant()
@@ -1158,6 +1165,7 @@ def test_delete_duplicates_non_identical(caplog, tmpdir):
     wait_recording_done(hass)
     wait_recording_done(hass)
     hass.stop()
+    dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     assert "Deleted 2 duplicated statistics rows" in caplog.text
     assert "Deleted 1 non identical" in caplog.text
@@ -1249,6 +1257,7 @@ def test_delete_duplicates_short_term(caplog, tmpdir):
             )
 
         hass.stop()
+        dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     # Test that the duplicates are removed during migration from schema 23
     hass = get_test_home_assistant()
@@ -1258,6 +1267,7 @@ def test_delete_duplicates_short_term(caplog, tmpdir):
     wait_recording_done(hass)
     wait_recording_done(hass)
     hass.stop()
+    dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
 
     assert "duplicated statistics rows" not in caplog.text
     assert "Found non identical" not in caplog.text
diff --git a/tests/components/risco/test_sensor.py b/tests/components/risco/test_sensor.py
index 4286a7d09c9..24efbabf087 100644
--- a/tests/components/risco/test_sensor.py
+++ b/tests/components/risco/test_sensor.py
@@ -168,6 +168,7 @@ def _check_state(hass, category, entity_id):
 
 async def test_setup(hass, two_zone_alarm):  # noqa: F811
     """Test entity setup."""
+    hass.config.set_time_zone("UTC")
     registry = er.async_get(hass)
 
     for id in ENTITY_IDS.values():
diff --git a/tests/components/sensor/test_recorder.py b/tests/components/sensor/test_recorder.py
index 155060222c8..af1494b381e 100644
--- a/tests/components/sensor/test_recorder.py
+++ b/tests/components/sensor/test_recorder.py
@@ -2176,6 +2176,8 @@ def test_compile_statistics_hourly_daily_monthly_summary(
         "homeassistant.components.recorder.models.dt_util.utcnow", return_value=zero
     ):
         hass = hass_recorder()
+        # Remove this after dropping the use of the hass_recorder fixture
+        hass.config.set_time_zone("America/Regina")
     recorder = hass.data[DATA_INSTANCE]
     recorder._db_supports_row_number = db_supports_row_number
     setup_component(hass, "sensor", {})
diff --git a/tests/components/sonarr/test_sensor.py b/tests/components/sonarr/test_sensor.py
index c499dc0112f..1b17fc2726e 100644
--- a/tests/components/sonarr/test_sensor.py
+++ b/tests/components/sonarr/test_sensor.py
@@ -96,10 +96,10 @@ async def test_sensors(
     assert state
     assert state.attributes.get(ATTR_ICON) == "mdi:television"
     assert state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) == "Episodes"
-    assert state.attributes.get("Bob's Burgers S04E11") == "2014-01-27T01:30:00+00:00"
+    assert state.attributes.get("Bob's Burgers S04E11") == "2014-01-26T17:30:00-08:00"
     assert (
         state.attributes.get("The Andy Griffith Show S01E01")
-        == "1960-10-03T01:00:00+00:00"
+        == "1960-10-02T17:00:00-08:00"
     )
     assert state.state == "2"
 
diff --git a/tests/components/sun/test_trigger.py b/tests/components/sun/test_trigger.py
index 55c31da6c89..3b5f3af76ec 100644
--- a/tests/components/sun/test_trigger.py
+++ b/tests/components/sun/test_trigger.py
@@ -20,8 +20,6 @@ import homeassistant.util.dt as dt_util
 from tests.common import async_fire_time_changed, async_mock_service, mock_component
 from tests.components.blueprint.conftest import stub_blueprint_populate  # noqa: F401
 
-ORIG_TIME_ZONE = dt_util.DEFAULT_TIME_ZONE
-
 
 @pytest.fixture
 def calls(hass):
@@ -33,20 +31,11 @@ def calls(hass):
 def setup_comp(hass):
     """Initialize components."""
     mock_component(hass, "group")
-    hass.config.set_time_zone(hass.config.time_zone)
     hass.loop.run_until_complete(
         async_setup_component(hass, sun.DOMAIN, {sun.DOMAIN: {sun.CONF_ELEVATION: 0}})
     )
 
 
-@pytest.fixture(autouse=True)
-def teardown():
-    """Restore."""
-    yield
-
-    dt_util.set_default_time_zone(ORIG_TIME_ZONE)
-
-
 async def test_sunset_trigger(hass, calls, legacy_patchable_time):
     """Test the sunset trigger."""
     now = datetime(2015, 9, 15, 23, tzinfo=dt_util.UTC)
diff --git a/tests/components/template/test_sensor.py b/tests/components/template/test_sensor.py
index 0352080bed8..b9b1a0cd93b 100644
--- a/tests/components/template/test_sensor.py
+++ b/tests/components/template/test_sensor.py
@@ -1124,7 +1124,8 @@ async def test_trigger_entity_device_class_parsing_works(hass):
 
     await hass.async_block_till_done()
 
-    now = dt_util.now()
+    # State of timestamp sensors are always in UTC
+    now = dt_util.utcnow()
 
     with patch("homeassistant.util.dt.now", return_value=now):
         hass.bus.async_fire("test_event")
@@ -1184,7 +1185,8 @@ async def test_trigger_entity_device_class_errors_works(hass):
 
 async def test_entity_device_class_parsing_works(hass):
     """Test entity device class parsing works."""
-    now = dt_util.now()
+    # State of timestamp sensors are always in UTC
+    now = dt_util.utcnow()
 
     with patch("homeassistant.util.dt.now", return_value=now):
         assert await async_setup_component(
diff --git a/tests/components/time_date/test_sensor.py b/tests/components/time_date/test_sensor.py
index a9b5ea83c05..56f58221529 100644
--- a/tests/components/time_date/test_sensor.py
+++ b/tests/components/time_date/test_sensor.py
@@ -1,20 +1,9 @@
 """The tests for time_date sensor platform."""
 from unittest.mock import patch
 
-import pytest
-
 import homeassistant.components.time_date.sensor as time_date
 import homeassistant.util.dt as dt_util
 
-ORIG_TZ = dt_util.DEFAULT_TIME_ZONE
-
-
-@pytest.fixture(autouse=True)
-def restore_ts():
-    """Restore default TZ."""
-    yield
-    dt_util.DEFAULT_TIME_ZONE = ORIG_TZ
-
 
 # pylint: disable=protected-access
 async def test_intervals(hass):
@@ -45,6 +34,8 @@ async def test_intervals(hass):
 
 async def test_states(hass):
     """Test states of sensors."""
+    hass.config.set_time_zone("UTC")
+
     now = dt_util.utc_from_timestamp(1495068856)
     device = time_date.TimeDateSensor(hass, "time")
     device._update_internal_state(now)
@@ -79,9 +70,7 @@ async def test_states(hass):
 
 async def test_states_non_default_timezone(hass):
     """Test states of sensors in a timezone other than UTC."""
-    new_tz = dt_util.get_time_zone("America/New_York")
-    assert new_tz is not None
-    dt_util.set_default_time_zone(new_tz)
+    hass.config.set_time_zone("America/New_York")
 
     now = dt_util.utc_from_timestamp(1495068856)
     device = time_date.TimeDateSensor(hass, "time")
@@ -116,9 +105,7 @@ async def test_states_non_default_timezone(hass):
 # pylint: disable=no-member
 async def test_timezone_intervals(hass):
     """Test date sensor behavior in a timezone besides UTC."""
-    new_tz = dt_util.get_time_zone("America/New_York")
-    assert new_tz is not None
-    dt_util.set_default_time_zone(new_tz)
+    hass.config.set_time_zone("America/New_York")
 
     device = time_date.TimeDateSensor(hass, "date")
     now = dt_util.utc_from_timestamp(50000)
@@ -128,9 +115,7 @@ async def test_timezone_intervals(hass):
     # so the second day was 18000 + 86400
     assert next_time.timestamp() == 104400
 
-    new_tz = dt_util.get_time_zone("America/Edmonton")
-    assert new_tz is not None
-    dt_util.set_default_time_zone(new_tz)
+    hass.config.set_time_zone("America/Edmonton")
     now = dt_util.parse_datetime("2017-11-13 19:47:19-07:00")
     device = time_date.TimeDateSensor(hass, "date")
     with patch("homeassistant.util.dt.utcnow", return_value=now):
@@ -138,9 +123,7 @@ async def test_timezone_intervals(hass):
     assert next_time.timestamp() == dt_util.as_timestamp("2017-11-14 00:00:00-07:00")
 
     # Entering DST
-    new_tz = dt_util.get_time_zone("Europe/Prague")
-    assert new_tz is not None
-    dt_util.set_default_time_zone(new_tz)
+    hass.config.set_time_zone("Europe/Prague")
 
     now = dt_util.parse_datetime("2020-03-29 00:00+01:00")
     with patch("homeassistant.util.dt.utcnow", return_value=now):
@@ -168,11 +151,9 @@ async def test_timezone_intervals(hass):
     "homeassistant.util.dt.utcnow",
     return_value=dt_util.parse_datetime("2017-11-14 02:47:19-00:00"),
 )
-async def test_timezone_intervals_empty_parameter(hass):
+async def test_timezone_intervals_empty_parameter(utcnow_mock, hass):
     """Test get_interval() without parameters."""
-    new_tz = dt_util.get_time_zone("America/Edmonton")
-    assert new_tz is not None
-    dt_util.set_default_time_zone(new_tz)
+    hass.config.set_time_zone("America/Edmonton")
     device = time_date.TimeDateSensor(hass, "date")
     next_time = device.get_next_interval()
     assert next_time.timestamp() == dt_util.as_timestamp("2017-11-14 00:00:00-07:00")
diff --git a/tests/components/tod/test_binary_sensor.py b/tests/components/tod/test_binary_sensor.py
index 06f29436d6e..ecdabdb910d 100644
--- a/tests/components/tod/test_binary_sensor.py
+++ b/tests/components/tod/test_binary_sensor.py
@@ -12,8 +12,6 @@ import homeassistant.util.dt as dt_util
 
 from tests.common import assert_setup_component
 
-ORIG_TIMEZONE = dt_util.DEFAULT_TIME_ZONE
-
 
 @pytest.fixture(autouse=True)
 def mock_legacy_time(legacy_patchable_time):
@@ -28,13 +26,6 @@ def setup_fixture(hass):
     hass.config.longitude = 18.98583
 
 
-@pytest.fixture(autouse=True)
-def restore_timezone(hass):
-    """Make sure we change timezone."""
-    yield
-    dt_util.set_default_time_zone(ORIG_TIMEZONE)
-
-
 async def test_setup(hass):
     """Test the setup."""
     config = {
@@ -69,7 +60,9 @@ async def test_setup_no_sensors(hass):
 
 async def test_in_period_on_start(hass):
     """Test simple setting."""
-    test_time = datetime(2019, 1, 10, 18, 43, 0, tzinfo=dt_util.UTC)
+    test_time = datetime(
+        2019, 1, 10, 18, 43, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
     config = {
         "binary_sensor": [
             {
@@ -93,7 +86,9 @@ async def test_in_period_on_start(hass):
 
 async def test_midnight_turnover_before_midnight_inside_period(hass):
     """Test midnight turnover setting before midnight inside period ."""
-    test_time = datetime(2019, 1, 10, 22, 30, 0, tzinfo=dt_util.UTC)
+    test_time = datetime(
+        2019, 1, 10, 22, 30, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
     config = {
         "binary_sensor": [
             {"platform": "tod", "name": "Night", "after": "22:00", "before": "5:00"}
@@ -112,7 +107,9 @@ async def test_midnight_turnover_before_midnight_inside_period(hass):
 
 async def test_midnight_turnover_after_midnight_inside_period(hass):
     """Test midnight turnover setting before midnight inside period ."""
-    test_time = datetime(2019, 1, 10, 21, 0, 0, tzinfo=dt_util.UTC)
+    test_time = datetime(
+        2019, 1, 10, 21, 0, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
     config = {
         "binary_sensor": [
             {"platform": "tod", "name": "Night", "after": "22:00", "before": "5:00"}
@@ -184,7 +181,9 @@ async def test_after_happens_tomorrow(hass):
 
 async def test_midnight_turnover_after_midnight_outside_period(hass):
     """Test midnight turnover setting before midnight inside period ."""
-    test_time = datetime(2019, 1, 10, 20, 0, 0, tzinfo=dt_util.UTC)
+    test_time = datetime(
+        2019, 1, 10, 20, 0, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
 
     config = {
         "binary_sensor": [
@@ -201,7 +200,9 @@ async def test_midnight_turnover_after_midnight_outside_period(hass):
     state = hass.states.get("binary_sensor.night")
     assert state.state == STATE_OFF
 
-    switchover_time = datetime(2019, 1, 11, 4, 59, 0, tzinfo=dt_util.UTC)
+    switchover_time = datetime(
+        2019, 1, 11, 4, 59, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    )
     with patch(
         "homeassistant.components.tod.binary_sensor.dt_util.utcnow",
         return_value=switchover_time,
@@ -420,13 +421,13 @@ async def test_from_sunset_to_sunrise(hass):
 
 async def test_offset(hass):
     """Test offset."""
-    after = datetime(2019, 1, 10, 18, 0, 0, tzinfo=dt_util.UTC) + timedelta(
-        hours=1, minutes=34
-    )
+    after = datetime(
+        2019, 1, 10, 18, 0, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    ) + timedelta(hours=1, minutes=34)
 
-    before = datetime(2019, 1, 10, 22, 0, 0, tzinfo=dt_util.UTC) + timedelta(
-        hours=1, minutes=45
-    )
+    before = datetime(
+        2019, 1, 10, 22, 0, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    ) + timedelta(hours=1, minutes=45)
 
     entity_id = "binary_sensor.evening"
     config = {
@@ -499,9 +500,9 @@ async def test_offset(hass):
 
 async def test_offset_overnight(hass):
     """Test offset overnight."""
-    after = datetime(2019, 1, 10, 18, 0, 0, tzinfo=dt_util.UTC) + timedelta(
-        hours=1, minutes=34
-    )
+    after = datetime(
+        2019, 1, 10, 18, 0, 0, tzinfo=dt_util.get_time_zone(hass.config.time_zone)
+    ) + timedelta(hours=1, minutes=34)
     entity_id = "binary_sensor.evening"
     config = {
         "binary_sensor": [
@@ -890,8 +891,7 @@ async def test_sun_offset(hass):
 
 async def test_dst(hass):
     """Test sun event with offset."""
-    hass.config.time_zone = "CET"
-    dt_util.set_default_time_zone(dt_util.get_time_zone("CET"))
+    hass.config.set_time_zone("CET")
     test_time = datetime(2019, 3, 30, 3, 0, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
@@ -919,8 +919,7 @@ async def test_dst(hass):
 
 async def test_simple_before_after_does_not_loop_utc_not_in_range(hass):
     """Test simple before after."""
-    hass.config.time_zone = "UTC"
-    dt_util.set_default_time_zone(dt_util.UTC)
+    hass.config.set_time_zone("UTC")
     test_time = datetime(2019, 1, 10, 18, 43, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
@@ -948,8 +947,7 @@ async def test_simple_before_after_does_not_loop_utc_not_in_range(hass):
 
 async def test_simple_before_after_does_not_loop_utc_in_range(hass):
     """Test simple before after."""
-    hass.config.time_zone = "UTC"
-    dt_util.set_default_time_zone(dt_util.UTC)
+    hass.config.set_time_zone("UTC")
     test_time = datetime(2019, 1, 10, 22, 43, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
@@ -977,8 +975,7 @@ async def test_simple_before_after_does_not_loop_utc_in_range(hass):
 
 async def test_simple_before_after_does_not_loop_utc_fire_at_before(hass):
     """Test simple before after."""
-    hass.config.time_zone = "UTC"
-    dt_util.set_default_time_zone(dt_util.UTC)
+    hass.config.set_time_zone("UTC")
     test_time = datetime(2019, 1, 11, 6, 0, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
@@ -1006,8 +1003,7 @@ async def test_simple_before_after_does_not_loop_utc_fire_at_before(hass):
 
 async def test_simple_before_after_does_not_loop_utc_fire_at_after(hass):
     """Test simple before after."""
-    hass.config.time_zone = "UTC"
-    dt_util.set_default_time_zone(dt_util.UTC)
+    hass.config.set_time_zone("UTC")
     test_time = datetime(2019, 1, 10, 22, 0, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
@@ -1035,8 +1031,7 @@ async def test_simple_before_after_does_not_loop_utc_fire_at_after(hass):
 
 async def test_simple_before_after_does_not_loop_utc_both_before_now(hass):
     """Test simple before after."""
-    hass.config.time_zone = "UTC"
-    dt_util.set_default_time_zone(dt_util.UTC)
+    hass.config.set_time_zone("UTC")
     test_time = datetime(2019, 1, 10, 22, 0, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
@@ -1064,8 +1059,7 @@ async def test_simple_before_after_does_not_loop_utc_both_before_now(hass):
 
 async def test_simple_before_after_does_not_loop_berlin_not_in_range(hass):
     """Test simple before after."""
-    hass.config.time_zone = "Europe/Berlin"
-    dt_util.set_default_time_zone(dt_util.get_time_zone("Europe/Berlin"))
+    hass.config.set_time_zone("Europe/Berlin")
     test_time = datetime(2019, 1, 10, 18, 43, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
@@ -1093,8 +1087,7 @@ async def test_simple_before_after_does_not_loop_berlin_not_in_range(hass):
 
 async def test_simple_before_after_does_not_loop_berlin_in_range(hass):
     """Test simple before after."""
-    hass.config.time_zone = "Europe/Berlin"
-    dt_util.set_default_time_zone(dt_util.get_time_zone("Europe/Berlin"))
+    hass.config.set_time_zone("Europe/Berlin")
     test_time = datetime(2019, 1, 10, 23, 43, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
diff --git a/tests/components/vallox/test_sensor.py b/tests/components/vallox/test_sensor.py
index bd8ecbea905..7649799f56b 100644
--- a/tests/components/vallox/test_sensor.py
+++ b/tests/components/vallox/test_sensor.py
@@ -12,44 +12,29 @@ from .conftest import patch_metrics
 
 from tests.common import MockConfigEntry
 
-ORIG_TZ = dt.DEFAULT_TIME_ZONE
-
-
-@pytest.fixture(autouse=True)
-def reset_tz():
-    """Restore the default TZ after test runs."""
-    yield
-    dt.DEFAULT_TIME_ZONE = ORIG_TZ
-
 
 @pytest.fixture
 def set_tz(request):
     """Set the default TZ to the one requested."""
-    return request.getfixturevalue(request.param)
+    request.getfixturevalue(request.param)
 
 
 @pytest.fixture
-def utc() -> tzinfo:
+def utc(hass: HomeAssistant) -> None:
     """Set the default TZ to UTC."""
-    tz = dt.get_time_zone("UTC")
-    dt.set_default_time_zone(tz)
-    return tz
+    hass.config.set_time_zone("UTC")
 
 
 @pytest.fixture
-def helsinki() -> tzinfo:
+def helsinki(hass: HomeAssistant) -> None:
     """Set the default TZ to Europe/Helsinki."""
-    tz = dt.get_time_zone("Europe/Helsinki")
-    dt.set_default_time_zone(tz)
-    return tz
+    hass.config.set_time_zone("Europe/Helsinki")
 
 
 @pytest.fixture
-def new_york() -> tzinfo:
+def new_york(hass: HomeAssistant) -> None:
     """Set the default TZ to America/New_York."""
-    tz = dt.get_time_zone("America/New_York")
-    dt.set_default_time_zone(tz)
-    return tz
+    hass.config.set_time_zone("America/New_York")
 
 
 def _sensor_to_datetime(sensor):
diff --git a/tests/components/zodiac/test_sensor.py b/tests/components/zodiac/test_sensor.py
index 6c784d3998f..90b19e73b04 100644
--- a/tests/components/zodiac/test_sensor.py
+++ b/tests/components/zodiac/test_sensor.py
@@ -35,6 +35,7 @@ DAY3 = datetime(2020, 4, 21, tzinfo=dt_util.UTC)
 )
 async def test_zodiac_day(hass, now, sign, element, modality):
     """Test the zodiac sensor."""
+    hass.config.set_time_zone("UTC")
     config = {DOMAIN: {}}
 
     with patch("homeassistant.components.zodiac.sensor.utcnow", return_value=now):
diff --git a/tests/conftest.py b/tests/conftest.py
index 902fc55eac4..a7dcef31591 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -29,7 +29,7 @@ from homeassistant.components.websocket_api.http import URL
 from homeassistant.const import ATTR_NOW, EVENT_TIME_CHANGED, HASSIO_USER_NAME
 from homeassistant.helpers import config_entry_oauth2_flow, event
 from homeassistant.setup import async_setup_component
-from homeassistant.util import location
+from homeassistant.util import dt as dt_util, location
 
 from tests.ignore_uncaught_exceptions import IGNORE_UNCAUGHT_EXCEPTIONS
 
@@ -249,6 +249,8 @@ def load_registries():
 def hass(loop, load_registries, hass_storage, request):
     """Fixture to provide a test instance of Home Assistant."""
 
+    orig_tz = dt_util.DEFAULT_TIME_ZONE
+
     def exc_handle(loop, context):
         """Handle exceptions by rethrowing them, which will fail the test."""
         # Most of these contexts will contain an exception, but not all.
@@ -273,6 +275,10 @@ def hass(loop, load_registries, hass_storage, request):
     yield hass
 
     loop.run_until_complete(hass.async_stop(force=True))
+
+    # Restore timezone, it is set when creating the hass object
+    dt_util.DEFAULT_TIME_ZONE = orig_tz
+
     for ex in exceptions:
         if (
             request.module.__name__,
diff --git a/tests/helpers/test_condition.py b/tests/helpers/test_condition.py
index ffbc2130f3b..2b5c35f06ad 100644
--- a/tests/helpers/test_condition.py
+++ b/tests/helpers/test_condition.py
@@ -28,8 +28,6 @@ import homeassistant.util.dt as dt_util
 
 from tests.common import async_mock_service
 
-ORIG_TIME_ZONE = dt_util.DEFAULT_TIME_ZONE
-
 
 @pytest.fixture
 def calls(hass):
@@ -46,14 +44,6 @@ def setup_comp(hass):
     )
 
 
-@pytest.fixture(autouse=True)
-def teardown():
-    """Restore."""
-    yield
-
-    dt_util.set_default_time_zone(ORIG_TIME_ZONE)
-
-
 def assert_element(trace_element, expected_element, path):
     """Assert a trace element is as expected.
 
@@ -2659,8 +2649,7 @@ async def test_if_action_before_sunrise_no_offset_kotzebue(hass, hass_ws_client,
     at 7 AM and sunset at 3AM during summer
     After sunrise is true from sunrise until midnight, local time.
     """
-    tz = dt_util.get_time_zone("America/Anchorage")
-    dt_util.set_default_time_zone(tz)
+    hass.config.set_time_zone("America/Anchorage")
     hass.config.latitude = 66.5
     hass.config.longitude = 162.4
     await async_setup_component(
@@ -2736,8 +2725,7 @@ async def test_if_action_after_sunrise_no_offset_kotzebue(hass, hass_ws_client,
     at 7 AM and sunset at 3AM during summer
     Before sunrise is true from midnight until sunrise, local time.
     """
-    tz = dt_util.get_time_zone("America/Anchorage")
-    dt_util.set_default_time_zone(tz)
+    hass.config.set_time_zone("America/Anchorage")
     hass.config.latitude = 66.5
     hass.config.longitude = 162.4
     await async_setup_component(
@@ -2813,8 +2801,7 @@ async def test_if_action_before_sunset_no_offset_kotzebue(hass, hass_ws_client,
     at 7 AM and sunset at 3AM during summer
     Before sunset is true from midnight until sunset, local time.
     """
-    tz = dt_util.get_time_zone("America/Anchorage")
-    dt_util.set_default_time_zone(tz)
+    hass.config.set_time_zone("America/Anchorage")
     hass.config.latitude = 66.5
     hass.config.longitude = 162.4
     await async_setup_component(
@@ -2890,8 +2877,7 @@ async def test_if_action_after_sunset_no_offset_kotzebue(hass, hass_ws_client, c
     at 7 AM and sunset at 3AM during summer
     After sunset is true from sunset until midnight, local time.
     """
-    tz = dt_util.get_time_zone("America/Anchorage")
-    dt_util.set_default_time_zone(tz)
+    hass.config.set_time_zone("America/Anchorage")
     hass.config.latitude = 66.5
     hass.config.longitude = 162.4
     await async_setup_component(
diff --git a/tests/helpers/test_event.py b/tests/helpers/test_event.py
index bd17aec92e6..67fc679bb8b 100644
--- a/tests/helpers/test_event.py
+++ b/tests/helpers/test_event.py
@@ -46,14 +46,6 @@ from tests.common import async_fire_time_changed
 DEFAULT_TIME_ZONE = dt_util.DEFAULT_TIME_ZONE
 
 
-@pytest.fixture(autouse=True)
-def teardown():
-    """Stop everything that was started."""
-    yield
-
-    dt_util.set_default_time_zone(DEFAULT_TIME_ZONE)
-
-
 async def test_track_point_in_time(hass):
     """Test track point in time."""
     before_birthday = datetime(1985, 7, 9, 12, 0, 0, tzinfo=dt_util.UTC)
@@ -3751,8 +3743,7 @@ async def test_periodic_task_duplicate_time(hass):
 @pytest.mark.freeze_time("2021-03-28 01:28:00+01:00")
 async def test_periodic_task_entering_dst(hass, freezer):
     """Test periodic task behavior when entering dst."""
-    timezone = dt_util.get_time_zone("Europe/Vienna")
-    dt_util.set_default_time_zone(timezone)
+    hass.config.set_time_zone("Europe/Vienna")
     specific_runs = []
 
     today = date.today().isoformat()
@@ -3801,8 +3792,7 @@ async def test_periodic_task_entering_dst_2(hass, freezer):
 
     This tests a task firing every second in the range 0..58 (not *:*:59)
     """
-    timezone = dt_util.get_time_zone("Europe/Vienna")
-    dt_util.set_default_time_zone(timezone)
+    hass.config.set_time_zone("Europe/Vienna")
     specific_runs = []
 
     today = date.today().isoformat()
@@ -3850,8 +3840,7 @@ async def test_periodic_task_entering_dst_2(hass, freezer):
 @pytest.mark.freeze_time("2021-10-31 02:28:00+02:00")
 async def test_periodic_task_leaving_dst(hass, freezer):
     """Test periodic task behavior when leaving dst."""
-    timezone = dt_util.get_time_zone("Europe/Vienna")
-    dt_util.set_default_time_zone(timezone)
+    hass.config.set_time_zone("Europe/Vienna")
     specific_runs = []
 
     today = date.today().isoformat()
@@ -3925,8 +3914,7 @@ async def test_periodic_task_leaving_dst(hass, freezer):
 @pytest.mark.freeze_time("2021-10-31 02:28:00+02:00")
 async def test_periodic_task_leaving_dst_2(hass, freezer):
     """Test periodic task behavior when leaving dst."""
-    timezone = dt_util.get_time_zone("Europe/Vienna")
-    dt_util.set_default_time_zone(timezone)
+    hass.config.set_time_zone("Europe/Vienna")
     specific_runs = []
 
     today = date.today().isoformat()
@@ -4188,8 +4176,8 @@ async def test_async_track_point_in_time_cancel(hass):
     """Test cancel of async track point in time."""
 
     times = []
+    hass.config.set_time_zone("US/Hawaii")
     hst_tz = dt_util.get_time_zone("US/Hawaii")
-    dt_util.set_default_time_zone(hst_tz)
 
     @ha.callback
     def run_callback(local_time):
diff --git a/tests/helpers/test_template.py b/tests/helpers/test_template.py
index d70837bd088..bbb5e11be7f 100644
--- a/tests/helpers/test_template.py
+++ b/tests/helpers/test_template.py
@@ -674,6 +674,7 @@ def test_strptime(hass):
 
 def test_timestamp_custom(hass):
     """Test the timestamps to custom filter."""
+    hass.config.set_time_zone("UTC")
     now = dt_util.utcnow()
     tests = [
         (None, None, None, None),
@@ -700,6 +701,7 @@ def test_timestamp_custom(hass):
 
 def test_timestamp_local(hass):
     """Test the timestamps to local filter."""
+    hass.config.set_time_zone("UTC")
     tests = {None: None, 1469119144: "2016-07-21T16:39:04+00:00"}
 
     for inp, out in tests.items():
@@ -1290,10 +1292,7 @@ def test_today_at(mock_is_safe, hass, now, expected, expected_midnight, timezone
     freezer = freeze_time(now)
     freezer.start()
 
-    original_tz = dt_util.DEFAULT_TIME_ZONE
-
-    timezone = dt_util.get_time_zone(timezone_str)
-    dt_util.set_default_time_zone(timezone)
+    hass.config.set_time_zone(timezone_str)
 
     result = template.Template(
         "{{ today_at('10:00').isoformat() }}",
@@ -1323,7 +1322,6 @@ def test_today_at(mock_is_safe, hass, now, expected, expected_midnight, timezone
         template.Template("{{ today_at('bad') }}", hass).async_render()
 
     freezer.stop()
-    dt_util.set_default_time_zone(original_tz)
 
 
 @patch(
@@ -1332,6 +1330,7 @@ def test_today_at(mock_is_safe, hass, now, expected, expected_midnight, timezone
 )
 def test_relative_time(mock_is_safe, hass):
     """Test relative_time method."""
+    hass.config.set_time_zone("UTC")
     now = datetime.strptime("2000-01-01 10:00:00 +00:00", "%Y-%m-%d %H:%M:%S %z")
     with patch("homeassistant.util.dt.now", return_value=now):
         result = template.Template(
diff --git a/tests/test_bootstrap.py b/tests/test_bootstrap.py
index 87d93c1a1ac..c6c507a0f73 100644
--- a/tests/test_bootstrap.py
+++ b/tests/test_bootstrap.py
@@ -12,7 +12,6 @@ import homeassistant.config as config_util
 from homeassistant.const import SIGNAL_BOOTSTRAP_INTEGRATONS
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers.dispatcher import async_dispatcher_connect
-import homeassistant.util.dt as dt_util
 
 from tests.common import (
     MockModule,
@@ -23,7 +22,6 @@ from tests.common import (
     mock_integration,
 )
 
-ORIG_TIMEZONE = dt_util.DEFAULT_TIME_ZONE
 VERSION_PATH = os.path.join(get_test_config_dir(), config_util.VERSION_FILE)
 
 
diff --git a/tests/test_config.py b/tests/test_config.py
index 4e761bc3f47..552139fa0ef 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -32,7 +32,6 @@ from homeassistant.helpers import config_validation as cv
 import homeassistant.helpers.check_config as check_config
 from homeassistant.helpers.entity import Entity
 from homeassistant.loader import async_get_integration
-from homeassistant.util import dt as dt_util
 from homeassistant.util.yaml import SECRET_YAML
 
 from tests.common import get_test_config_dir, patch_yaml_files
@@ -44,7 +43,6 @@ VERSION_PATH = os.path.join(CONFIG_DIR, config_util.VERSION_FILE)
 AUTOMATIONS_PATH = os.path.join(CONFIG_DIR, config_util.AUTOMATION_CONFIG_PATH)
 SCRIPTS_PATH = os.path.join(CONFIG_DIR, config_util.SCRIPT_CONFIG_PATH)
 SCENES_PATH = os.path.join(CONFIG_DIR, config_util.SCENE_CONFIG_PATH)
-ORIG_TIMEZONE = dt_util.DEFAULT_TIME_ZONE
 
 
 def create_file(path):
@@ -58,8 +56,6 @@ def teardown():
     """Clean up."""
     yield
 
-    dt_util.DEFAULT_TIME_ZONE = ORIG_TIMEZONE
-
     if os.path.isfile(YAML_PATH):
         os.remove(YAML_PATH)