Thanks for your tips. I'll have a look at the software you suggest. If it won't work in my case I'll get in touch with support.
The Pro Weather Link app looks a bit confusing, I understand. Nevertheless the Weather Underground does not belong to the bottom window where I tried to type in the right Windy url and credentials.
I tried to edit the previous post for others but it won't let me even though the 3600 seconds of editing lock have passed.
Anyway, here it is a bit more clear I hope for others to understand it better.