diff --git a/CHANGELOG.md b/CHANGELOG.md
index cce4d596b..2c04c91a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased/Snapshot]
 
-### Added 
+### Added
+-Added weathersource documentation [#1390](https://github.com/ie3-institute/PowerSystemDataModel/issues/1390)
 
 ### Fixed
 
diff --git a/docs/readthedocs/models/input/additionaldata/weathersource.md b/docs/readthedocs/models/input/additionaldata/weathersource.md
new file mode 100644
index 000000000..b06322076
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+++ b/docs/readthedocs/models/input/additionaldata/weathersource.md
@@ -0,0 +1,66 @@
+# WeatherSource
+
+The **`WeatherSource`** is an abstract class that provides a standardized interface for accessing time-series weather data. It serves as a foundation for concrete implementations that fetch data from various providers (e.g., CSV files or SQL databases).
+
+A `WeatherSource` relies on two key components:
+* **[`IdCoordinateSource`](idcoordinatesource.md)**: Used to resolve a numeric **coordinate ID** from the source data into a geographic `Point` object.
+* **`TimeBasedWeatherValueFactory`**: Used to construct `WeatherValue` objects from the raw data fields.
+
+***
+
+## Information
+
+The source data for any `WeatherSource` implementation is expected to contain the following information.
+
+```{list-table}
+   :widths: auto
+   :class: wrapping
+   :header-rows: 1
+
+   * - Attribute
+     - Remarks
+
+   * - **`coordinateid`**
+     - An **integer ID** for a specific geographic coordinate. This ID is used to look up the actual `Point` via the `IdCoordinateSource`.
+
+   * - **Time**
+     - The specific timestamp of the weather data, typically as a `ZonedDateTime`.
+
+   * - **Weather Data**
+     - The meteorological values, such as solar irradiance (`direct` and `diffuse`), temperature, and wind data (`speed` and `direction`).
+```
+
+## WeatherData
+
+Weather data is comprised of five key components:
+
+```{list-table}
+   :widths: auto
+   :class: wrapping
+   :header-rows: 1
+
+   * - Component
+     - Description
+     - Unit
+
+   * - **`directIrradiance`**
+     - Solar radiation that reaches the surface directly from the sun.
+     - W/m²
+
+   * - **`diffuseIrradiance`**
+     - Solar radiation scattered by the atmosphere before reaching the surface.
+     - W/m²
+
+   * - **`temperature`**
+     - Ambient air temperature.
+     - K (Kelvin)
+
+   * - **`windVelocity`**
+     - Wind speed.
+     - m/s (meters per second)
+
+   * - **`windDirection`**
+     - Wind direction, where 0° is North, 90° is East, etc.
+     - ° (degrees)
+```
+Weather data in COSMO and ICON formats is supported. Additional optional weather data can also be provided.
\ No newline at end of file
diff --git a/docs/readthedocs/models/models.md b/docs/readthedocs/models/models.md
index 390d650cb..0803c7777 100644
--- a/docs/readthedocs/models/models.md
+++ b/docs/readthedocs/models/models.md
@@ -168,6 +168,7 @@ maxdepth: 1
 ---
 input/additionaldata/timeseries
 input/additionaldata/idcoordinatesource
+input/additionaldata/weathersource
 ```
 
 ## Result