@sdetweil as long as it keeps working with 2.5, I’ll keep it. Once it won’t work, I’ll subscribe for 3.0.

@sdetweil that’s really weird, as I have proof it’s working.

@sdetweil thanks a lot for your reply!

I can see in the console log:

GET https://api.openweathermap.org/data/3.0/forecast?id=2516479&units=metric&lang=de&APPID=%my_api_key_here%

Status code: 404 not found

When I call the URL with my browser I get

{"cod":"404","message":"Method not supported"}

AAH!
So, I see that the weather module does not call “2.5” per default, as written in the documentation, but it’s the 3.0 API being called, where the construct of the URL won’t help. So, I’ll add

apiVersion:"2.5",

to my configuration of the weather module!

Once changed, it worked out!
Thanks a lot for that hint! I spent about 6 hours of my day on this without applying troubeshooting 101 by not looking in the browser console log …