Oh well! Good to know! Next time I'll use DWD instead of using those weird apps. Thanks!
No the DWD is not allowed to provide a weather app I believe. Because it would compete with commercial apps. It offers an app which issues weather warnings though.
DWD is allowed to provide a weather app, but not for free. So they offer it for a nominal one-time fee instead.
Windy.com gives you ECMWF. ECMWF has a much stronger model.