diff --git a/homeassistant/components/metoffice/weather.py b/homeassistant/components/metoffice/weather.py
index 56d94409db5..6ce1a49e6f1 100644
--- a/homeassistant/components/metoffice/weather.py
+++ b/homeassistant/components/metoffice/weather.py
@@ -8,7 +8,7 @@ from homeassistant.components.weather import (
     ATTR_FORECAST_WIND_SPEED,
     WeatherEntity,
 )
-from homeassistant.const import LENGTH_KILOMETERS, TEMP_CELSIUS
+from homeassistant.const import TEMP_CELSIUS
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.typing import ConfigType
 from homeassistant.helpers.update_coordinator import CoordinatorEntity
@@ -117,11 +117,6 @@ class MetOfficeWeather(CoordinatorEntity, WeatherEntity):
             _visibility = f"{visibility_class} - {visibility_distance}"
         return _visibility
 
-    @property
-    def visibility_unit(self):
-        """Return the unit of measurement."""
-        return LENGTH_KILOMETERS
-
     @property
     def pressure(self):
         """Return the mean sea-level pressure."""
diff --git a/homeassistant/components/weather/__init__.py b/homeassistant/components/weather/__init__.py
index 81d245c19bb..b9fa7e2ae39 100644
--- a/homeassistant/components/weather/__init__.py
+++ b/homeassistant/components/weather/__init__.py
@@ -61,6 +61,8 @@ ENTITY_ID_FORMAT = DOMAIN + ".{}"
 
 SCAN_INTERVAL = timedelta(seconds=30)
 
+ROUNDING_PRECISION = 2
+
 
 class Forecast(TypedDict, total=False):
     """Typed weather forecast dict."""
@@ -112,38 +114,52 @@ class WeatherEntity(Entity):
     _attr_ozone: float | None = None
     _attr_precision: float
     _attr_pressure: float | None = None
+    _attr_pressure_unit: str | None = None
     _attr_state: None = None
     _attr_temperature_unit: str
     _attr_temperature: float | None
     _attr_visibility: float | None = None
+    _attr_visibility_unit: str | None = None
+    _attr_precipitation_unit: str | None = None
     _attr_wind_bearing: float | str | None = None
     _attr_wind_speed: float | None = None
+    _attr_wind_speed_unit: str | None = None
 
     @property
     def temperature(self) -> float | None:
-        """Return the platform temperature."""
+        """Return the platform temperature in native units (i.e. not converted)."""
         return self._attr_temperature
 
     @property
     def temperature_unit(self) -> str:
-        """Return the unit of measurement."""
+        """Return the native unit of measurement for temperature."""
         return self._attr_temperature_unit
 
     @property
     def pressure(self) -> float | None:
-        """Return the pressure."""
+        """Return the pressure in native units."""
         return self._attr_pressure
 
+    @property
+    def pressure_unit(self) -> str | None:
+        """Return the native unit of measurement for pressure."""
+        return self._attr_pressure_unit
+
     @property
     def humidity(self) -> float | None:
-        """Return the humidity."""
+        """Return the humidity in native units."""
         return self._attr_humidity
 
     @property
     def wind_speed(self) -> float | None:
-        """Return the wind speed."""
+        """Return the wind speed in native units."""
         return self._attr_wind_speed
 
+    @property
+    def wind_speed_unit(self) -> str | None:
+        """Return the native unit of measurement for wind speed."""
+        return self._attr_wind_speed_unit
+
     @property
     def wind_bearing(self) -> float | str | None:
         """Return the wind bearing."""
@@ -156,17 +172,27 @@ class WeatherEntity(Entity):
 
     @property
     def visibility(self) -> float | None:
-        """Return the visibility."""
+        """Return the visibility in native units."""
         return self._attr_visibility
 
+    @property
+    def visibility_unit(self) -> str | None:
+        """Return the native unit of measurement for visibility."""
+        return self._attr_visibility_unit
+
     @property
     def forecast(self) -> list[Forecast] | None:
-        """Return the forecast."""
+        """Return the forecast in native units."""
         return self._attr_forecast
 
+    @property
+    def precipitation_unit(self) -> str | None:
+        """Return the native unit of measurement for accumulated precipitation."""
+        return self._attr_precipitation_unit
+
     @property
     def precision(self) -> float:
-        """Return the precision of the temperature value."""
+        """Return the precision of the temperature value, after unit conversion."""
         if hasattr(self, "_attr_precision"):
             return self._attr_precision
         return (
@@ -178,11 +204,14 @@ class WeatherEntity(Entity):
     @final
     @property
     def state_attributes(self):
-        """Return the state attributes."""
+        """Return the state attributes, converted from native units to user-configured units."""
         data = {}
         if self.temperature is not None:
             data[ATTR_WEATHER_TEMPERATURE] = show_temp(
-                self.hass, self.temperature, self.temperature_unit, self.precision
+                self.hass,
+                self.temperature,
+                self.temperature_unit,
+                self.precision,
             )
 
         if (humidity := self.humidity) is not None:
@@ -192,15 +221,28 @@ class WeatherEntity(Entity):
             data[ATTR_WEATHER_OZONE] = ozone
 
         if (pressure := self.pressure) is not None:
+            if (unit := self.pressure_unit) is not None:
+                pressure = round(
+                    self.hass.config.units.pressure(pressure, unit), ROUNDING_PRECISION
+                )
             data[ATTR_WEATHER_PRESSURE] = pressure
 
         if (wind_bearing := self.wind_bearing) is not None:
             data[ATTR_WEATHER_WIND_BEARING] = wind_bearing
 
         if (wind_speed := self.wind_speed) is not None:
+            if (unit := self.wind_speed_unit) is not None:
+                wind_speed = round(
+                    self.hass.config.units.wind_speed(wind_speed, unit),
+                    ROUNDING_PRECISION,
+                )
             data[ATTR_WEATHER_WIND_SPEED] = wind_speed
 
         if (visibility := self.visibility) is not None:
+            if (unit := self.visibility_unit) is not None:
+                visibility = round(
+                    self.hass.config.units.length(visibility, unit), ROUNDING_PRECISION
+                )
             data[ATTR_WEATHER_VISIBILITY] = visibility
 
         if self.forecast is not None:
@@ -220,6 +262,34 @@ class WeatherEntity(Entity):
                         self.temperature_unit,
                         self.precision,
                     )
+                if ATTR_FORECAST_PRESSURE in forecast_entry:
+                    if (unit := self.pressure_unit) is not None:
+                        pressure = round(
+                            self.hass.config.units.pressure(
+                                forecast_entry[ATTR_FORECAST_PRESSURE], unit
+                            ),
+                            ROUNDING_PRECISION,
+                        )
+                        forecast_entry[ATTR_FORECAST_PRESSURE] = pressure
+                if ATTR_FORECAST_WIND_SPEED in forecast_entry:
+                    if (unit := self.wind_speed_unit) is not None:
+                        wind_speed = round(
+                            self.hass.config.units.wind_speed(
+                                forecast_entry[ATTR_FORECAST_WIND_SPEED], unit
+                            ),
+                            ROUNDING_PRECISION,
+                        )
+                        forecast_entry[ATTR_FORECAST_WIND_SPEED] = wind_speed
+                if ATTR_FORECAST_PRECIPITATION in forecast_entry:
+                    if (unit := self.precipitation_unit) is not None:
+                        precipitation = round(
+                            self.hass.config.units.accumulated_precipitation(
+                                forecast_entry[ATTR_FORECAST_PRECIPITATION], unit
+                            ),
+                            ROUNDING_PRECISION,
+                        )
+                        forecast_entry[ATTR_FORECAST_PRECIPITATION] = precipitation
+
                 forecast.append(forecast_entry)
 
             data[ATTR_FORECAST] = forecast
diff --git a/tests/components/weather/test_weather.py b/tests/components/demo/test_weather.py
similarity index 98%
rename from tests/components/weather/test_weather.py
rename to tests/components/demo/test_weather.py
index 3057532668a..c4ae8fcd79c 100644
--- a/tests/components/weather/test_weather.py
+++ b/tests/components/demo/test_weather.py
@@ -1,4 +1,4 @@
-"""The tests for the Weather component."""
+"""The tests for the demo weather component."""
 from homeassistant.components import weather
 from homeassistant.components.weather import (
     ATTR_FORECAST,
diff --git a/tests/components/weather/test_init.py b/tests/components/weather/test_init.py
new file mode 100644
index 00000000000..4125e94749a
--- /dev/null
+++ b/tests/components/weather/test_init.py
@@ -0,0 +1,170 @@
+"""The test for weather entity."""
+import pytest
+from pytest import approx
+
+from homeassistant.components.weather import (
+    ATTR_CONDITION_SUNNY,
+    ATTR_FORECAST,
+    ATTR_FORECAST_PRECIPITATION,
+    ATTR_FORECAST_PRESSURE,
+    ATTR_FORECAST_TEMP,
+    ATTR_FORECAST_TEMP_LOW,
+    ATTR_FORECAST_WIND_SPEED,
+    ATTR_WEATHER_PRESSURE,
+    ATTR_WEATHER_TEMPERATURE,
+    ATTR_WEATHER_VISIBILITY,
+    ATTR_WEATHER_WIND_SPEED,
+)
+from homeassistant.const import (
+    LENGTH_MILES,
+    LENGTH_MILLIMETERS,
+    PRESSURE_INHG,
+    SPEED_METERS_PER_SECOND,
+    TEMP_FAHRENHEIT,
+)
+from homeassistant.setup import async_setup_component
+from homeassistant.util.distance import convert as convert_distance
+from homeassistant.util.pressure import convert as convert_pressure
+from homeassistant.util.speed import convert as convert_speed
+from homeassistant.util.temperature import convert as convert_temperature
+from homeassistant.util.unit_system import IMPERIAL_SYSTEM, METRIC_SYSTEM
+
+
+async def create_entity(hass, **kwargs):
+    """Create the weather entity to run tests on."""
+    kwargs = {"temperature": None, "temperature_unit": None, **kwargs}
+    platform = getattr(hass.components, "test.weather")
+    platform.init(empty=True)
+    platform.ENTITIES.append(
+        platform.MockWeatherMockForecast(
+            name="Test", condition=ATTR_CONDITION_SUNNY, **kwargs
+        )
+    )
+
+    entity0 = platform.ENTITIES[0]
+    assert await async_setup_component(
+        hass, "weather", {"weather": {"platform": "test"}}
+    )
+    await hass.async_block_till_done()
+    return entity0
+
+
+@pytest.mark.parametrize("unit_system", [IMPERIAL_SYSTEM, METRIC_SYSTEM])
+async def test_temperature_conversion(
+    hass,
+    enable_custom_integrations,
+    unit_system,
+):
+    """Test temperature conversion."""
+    hass.config.units = unit_system
+    native_value = 38
+    native_unit = TEMP_FAHRENHEIT
+
+    entity0 = await create_entity(
+        hass, temperature=native_value, temperature_unit=native_unit
+    )
+
+    state = hass.states.get(entity0.entity_id)
+    forecast = state.attributes[ATTR_FORECAST][0]
+
+    expected = convert_temperature(
+        native_value, native_unit, unit_system.temperature_unit
+    )
+    assert float(state.attributes[ATTR_WEATHER_TEMPERATURE]) == approx(
+        expected, rel=0.1
+    )
+    assert float(forecast[ATTR_FORECAST_TEMP]) == approx(expected, rel=0.1)
+    assert float(forecast[ATTR_FORECAST_TEMP_LOW]) == approx(expected, rel=0.1)
+
+
+@pytest.mark.parametrize("unit_system", [IMPERIAL_SYSTEM, METRIC_SYSTEM])
+async def test_pressure_conversion(
+    hass,
+    enable_custom_integrations,
+    unit_system,
+):
+    """Test pressure conversion."""
+    hass.config.units = unit_system
+    native_value = 30
+    native_unit = PRESSURE_INHG
+
+    entity0 = await create_entity(
+        hass, pressure=native_value, pressure_unit=native_unit
+    )
+    state = hass.states.get(entity0.entity_id)
+    forecast = state.attributes[ATTR_FORECAST][0]
+
+    expected = convert_pressure(native_value, native_unit, unit_system.pressure_unit)
+    assert float(state.attributes[ATTR_WEATHER_PRESSURE]) == approx(expected, rel=1e-2)
+    assert float(forecast[ATTR_FORECAST_PRESSURE]) == approx(expected, rel=1e-2)
+
+
+@pytest.mark.parametrize("unit_system", [IMPERIAL_SYSTEM, METRIC_SYSTEM])
+async def test_wind_speed_conversion(
+    hass,
+    enable_custom_integrations,
+    unit_system,
+):
+    """Test wind speed conversion."""
+    hass.config.units = unit_system
+    native_value = 10
+    native_unit = SPEED_METERS_PER_SECOND
+
+    entity0 = await create_entity(
+        hass, wind_speed=native_value, wind_speed_unit=native_unit
+    )
+
+    state = hass.states.get(entity0.entity_id)
+    forecast = state.attributes[ATTR_FORECAST][0]
+
+    expected = convert_speed(native_value, native_unit, unit_system.wind_speed_unit)
+    assert float(state.attributes[ATTR_WEATHER_WIND_SPEED]) == approx(
+        expected, rel=1e-2
+    )
+    assert float(forecast[ATTR_FORECAST_WIND_SPEED]) == approx(expected, rel=1e-2)
+
+
+@pytest.mark.parametrize("unit_system", [IMPERIAL_SYSTEM, METRIC_SYSTEM])
+async def test_visibility_conversion(
+    hass,
+    enable_custom_integrations,
+    unit_system,
+):
+    """Test visibility conversion."""
+    hass.config.units = unit_system
+    native_value = 10
+    native_unit = LENGTH_MILES
+
+    entity0 = await create_entity(
+        hass, visibility=native_value, visibility_unit=native_unit
+    )
+
+    state = hass.states.get(entity0.entity_id)
+    expected = convert_distance(native_value, native_unit, unit_system.length_unit)
+    assert float(state.attributes[ATTR_WEATHER_VISIBILITY]) == approx(
+        expected, rel=1e-2
+    )
+
+
+@pytest.mark.parametrize("unit_system", [IMPERIAL_SYSTEM, METRIC_SYSTEM])
+async def test_precipitation_conversion(
+    hass,
+    enable_custom_integrations,
+    unit_system,
+):
+    """Test precipitation conversion."""
+    hass.config.units = unit_system
+    native_value = 30
+    native_unit = LENGTH_MILLIMETERS
+
+    entity0 = await create_entity(
+        hass, precipitation=native_value, precipitation_unit=native_unit
+    )
+
+    state = hass.states.get(entity0.entity_id)
+    forecast = state.attributes[ATTR_FORECAST][0]
+
+    expected = convert_distance(
+        native_value, native_unit, unit_system.accumulated_precipitation_unit
+    )
+    assert float(forecast[ATTR_FORECAST_PRECIPITATION]) == approx(expected, rel=1e-2)
diff --git a/tests/testing_config/custom_components/test/weather.py b/tests/testing_config/custom_components/test/weather.py
new file mode 100644
index 00000000000..224d6495548
--- /dev/null
+++ b/tests/testing_config/custom_components/test/weather.py
@@ -0,0 +1,126 @@
+"""
+Provide a mock weather platform.
+
+Call init before using it in your tests to ensure clean test data.
+"""
+from __future__ import annotations
+
+from homeassistant.components.weather import (
+    ATTR_FORECAST_PRECIPITATION,
+    ATTR_FORECAST_PRESSURE,
+    ATTR_FORECAST_TEMP,
+    ATTR_FORECAST_TEMP_LOW,
+    ATTR_FORECAST_WIND_BEARING,
+    ATTR_FORECAST_WIND_SPEED,
+    Forecast,
+    WeatherEntity,
+)
+
+from tests.common import MockEntity
+
+ENTITIES = []
+
+
+def init(empty=False):
+    """Initialize the platform with entities."""
+    global ENTITIES
+    ENTITIES = [] if empty else [MockWeather()]
+
+
+async def async_setup_platform(
+    hass, config, async_add_entities_callback, discovery_info=None
+):
+    """Return mock entities."""
+    async_add_entities_callback(ENTITIES)
+
+
+class MockWeather(MockEntity, WeatherEntity):
+    """Mock weather class."""
+
+    @property
+    def temperature(self) -> float | None:
+        """Return the platform temperature."""
+        return self._handle("temperature")
+
+    @property
+    def temperature_unit(self) -> str | None:
+        """Return the unit of measurement for temperature."""
+        return self._handle("temperature_unit")
+
+    @property
+    def pressure(self) -> float | None:
+        """Return the pressure."""
+        return self._handle("pressure")
+
+    @property
+    def pressure_unit(self) -> str | None:
+        """Return the unit of measurement for pressure."""
+        return self._handle("pressure_unit")
+
+    @property
+    def humidity(self) -> float | None:
+        """Return the humidity."""
+        return self._handle("humidity")
+
+    @property
+    def wind_speed(self) -> float | None:
+        """Return the wind speed."""
+        return self._handle("wind_speed")
+
+    @property
+    def wind_speed_unit(self) -> str | None:
+        """Return the unit of measurement for wind speed."""
+        return self._handle("wind_speed_unit")
+
+    @property
+    def wind_bearing(self) -> float | str | None:
+        """Return the wind bearing."""
+        return self._handle("wind_bearing")
+
+    @property
+    def ozone(self) -> float | None:
+        """Return the ozone level."""
+        return self._handle("ozone")
+
+    @property
+    def visibility(self) -> float | None:
+        """Return the visibility."""
+        return self._handle("visibility")
+
+    @property
+    def visibility_unit(self) -> str | None:
+        """Return the unit of measurement for visibility."""
+        return self._handle("visibility_unit")
+
+    @property
+    def forecast(self) -> list[Forecast] | None:
+        """Return the forecast."""
+        return self._handle("forecast")
+
+    @property
+    def precipitation_unit(self) -> str | None:
+        """Return the native unit of measurement for accumulated precipitation."""
+        return self._handle("precipitation_unit")
+
+    @property
+    def condition(self) -> str | None:
+        """Return the current condition."""
+        return self._handle("condition")
+
+
+class MockWeatherMockForecast(MockWeather):
+    """Mock weather class with mocked forecast."""
+
+    @property
+    def forecast(self) -> list[Forecast] | None:
+        """Return the forecast."""
+        return [
+            {
+                ATTR_FORECAST_TEMP: self.temperature,
+                ATTR_FORECAST_TEMP_LOW: self.temperature,
+                ATTR_FORECAST_PRESSURE: self.pressure,
+                ATTR_FORECAST_WIND_SPEED: self.wind_speed,
+                ATTR_FORECAST_WIND_BEARING: self.wind_bearing,
+                ATTR_FORECAST_PRECIPITATION: self._values.get("precipitation"),
+            }
+        ]