Open-Meteo

No registration is required at all! See https://open-meteo.com/en/docs

- openmeteo:
      label: Kyiv # optional
      latitude: 50.449684
      longitude: 30.525026
      timezone: Europe/Kiev # optional
      units: metric # or imperial
      cache: 5 # Time in minutes to cache API responses, to stay within limits

You can optionally not pass a latitude and longitude and the widget will use your current location (requires a secure context, eg. HTTPS).