diff --git a/homeassistant/components/accuweather/weather.py b/homeassistant/components/accuweather/weather.py
index 4d248a06ac3..576b77ee0cb 100644
--- a/homeassistant/components/accuweather/weather.py
+++ b/homeassistant/components/accuweather/weather.py
@@ -31,7 +31,6 @@ from homeassistant.const import (
 )
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
-from homeassistant.helpers.update_coordinator import TimestampDataUpdateCoordinator
 from homeassistant.util.dt import utc_from_timestamp
 
 from . import AccuWeatherData
@@ -65,8 +64,6 @@ class AccuWeatherEntity(
     CoordinatorWeatherEntity[
         AccuWeatherObservationDataUpdateCoordinator,
         AccuWeatherDailyForecastDataUpdateCoordinator,
-        TimestampDataUpdateCoordinator,
-        TimestampDataUpdateCoordinator,
     ]
 ):
     """Define an AccuWeather entity."""
diff --git a/homeassistant/components/metoffice/weather.py b/homeassistant/components/metoffice/weather.py
index 33fec874611..5eeddee8dd4 100644
--- a/homeassistant/components/metoffice/weather.py
+++ b/homeassistant/components/metoffice/weather.py
@@ -91,8 +91,6 @@ class MetOfficeWeather(
     CoordinatorWeatherEntity[
         TimestampDataUpdateCoordinator[MetOfficeData],
         TimestampDataUpdateCoordinator[MetOfficeData],
-        TimestampDataUpdateCoordinator[MetOfficeData],
-        TimestampDataUpdateCoordinator[MetOfficeData],  # Can be removed in Python 3.12
     ]
 ):
     """Implementation of a Met Office weather condition."""
diff --git a/homeassistant/components/nws/weather.py b/homeassistant/components/nws/weather.py
index c017d579c3a..f25998f1504 100644
--- a/homeassistant/components/nws/weather.py
+++ b/homeassistant/components/nws/weather.py
@@ -35,6 +35,7 @@ from homeassistant.const import (
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.helpers import entity_registry as er
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.update_coordinator import TimestampDataUpdateCoordinator
 from homeassistant.util.unit_conversion import SpeedConverter, TemperatureConverter
 
 from . import NWSData, base_unique_id, device_info
@@ -110,7 +111,7 @@ def _calculate_unique_id(entry_data: MappingProxyType[str, Any], mode: str) -> s
     return f"{base_unique_id(latitude, longitude)}_{mode}"
 
 
-class NWSWeather(CoordinatorWeatherEntity):
+class NWSWeather(CoordinatorWeatherEntity[TimestampDataUpdateCoordinator[None]]):
     """Representation of a weather condition."""
 
     _attr_attribution = ATTRIBUTION
diff --git a/homeassistant/components/weather/__init__.py b/homeassistant/components/weather/__init__.py
index c92c5d232ba..048e969b238 100644
--- a/homeassistant/components/weather/__init__.py
+++ b/homeassistant/components/weather/__init__.py
@@ -8,18 +8,9 @@ from contextlib import suppress
 from datetime import timedelta
 from functools import cached_property, partial
 import logging
-from typing import (
-    Any,
-    Final,
-    Generic,
-    Literal,
-    Required,
-    TypedDict,
-    TypeVar,
-    cast,
-    final,
-)
+from typing import Any, Final, Generic, Literal, Required, TypedDict, cast, final
 
+from typing_extensions import TypeVar
 import voluptuous as vol
 
 from homeassistant.config_entries import ConfigEntry
@@ -137,21 +128,25 @@ LEGACY_SERVICE_GET_FORECAST: Final = "get_forecast"
 SERVICE_GET_FORECASTS: Final = "get_forecasts"
 
 _ObservationUpdateCoordinatorT = TypeVar(
-    "_ObservationUpdateCoordinatorT", bound="DataUpdateCoordinator[Any]"
+    "_ObservationUpdateCoordinatorT",
+    bound=DataUpdateCoordinator[Any],
+    default=DataUpdateCoordinator[dict[str, Any]],
 )
 
-# Note:
-# Mypy bug https://github.com/python/mypy/issues/9424 prevents us from making the
-# forecast cooordinators optional, bound=TimestampDataUpdateCoordinator[Any] | None
-
 _DailyForecastUpdateCoordinatorT = TypeVar(
-    "_DailyForecastUpdateCoordinatorT", bound="TimestampDataUpdateCoordinator[Any]"
+    "_DailyForecastUpdateCoordinatorT",
+    bound=TimestampDataUpdateCoordinator[Any],
+    default=TimestampDataUpdateCoordinator[None],
 )
 _HourlyForecastUpdateCoordinatorT = TypeVar(
-    "_HourlyForecastUpdateCoordinatorT", bound="TimestampDataUpdateCoordinator[Any]"
+    "_HourlyForecastUpdateCoordinatorT",
+    bound=TimestampDataUpdateCoordinator[Any],
+    default=_DailyForecastUpdateCoordinatorT,
 )
 _TwiceDailyForecastUpdateCoordinatorT = TypeVar(
-    "_TwiceDailyForecastUpdateCoordinatorT", bound="TimestampDataUpdateCoordinator[Any]"
+    "_TwiceDailyForecastUpdateCoordinatorT",
+    bound=TimestampDataUpdateCoordinator[Any],
+    default=_DailyForecastUpdateCoordinatorT,
 )
 
 # mypy: disallow-any-generics
@@ -1244,19 +1239,12 @@ class CoordinatorWeatherEntity(
 
 class SingleCoordinatorWeatherEntity(
     CoordinatorWeatherEntity[
-        _ObservationUpdateCoordinatorT,
-        TimestampDataUpdateCoordinator[None],
-        TimestampDataUpdateCoordinator[None],
-        TimestampDataUpdateCoordinator[None],
+        _ObservationUpdateCoordinatorT, TimestampDataUpdateCoordinator[None]
     ],
 ):
     """A class for weather entities using a single DataUpdateCoordinators.
 
-    This class is added as a convenience because:
-    - Deriving from CoordinatorWeatherEntity requires specifying all type parameters
-    until we upgrade to Python 3.12 which supports defaults
-    - Mypy bug https://github.com/python/mypy/issues/9424 prevents us from making the
-    forecast cooordinator type vars optional
+    This class is added as a convenience.
     """
 
     def __init__(