The weather-widgets get their information from a weather-service. Each service works
a little bit different especially the 'location' format.
The location format must be 'Tyskland/Bayern/Würzburg'. Go to the webpage to get your location from the url.
You need a key for that service (but Wunderground will no longer provide free weather API keys).
You need a key for that service. Go to the webpage to generate your own key.
Note: Darksky does only support geo coordinates as latitude,longitude (e.g. 47.3537,8.0317) and no city names.
Choose your service and enter your location and key on the configuration