If activated by your user this addon adds a widget to the users network tab sidebar showing current weather informations (temperature, relative humidity, wind conditions and preassure) from OpenWeatherMap. The user can configure the location as e.g. Berlin,DE or the zip code "14476,DE".
The language for the request at OpenWeatherMap is set to the UI language of friendica. If the string for the description of the current weather conditions is available in this language depends on OpenWeatherMap, fallback is english.
You should get an APPID from OpenWeatherMap if you want to use this widget. You can register here.