@ivo True that. After a lot of looking, I finally found out how you could access the Deutscher Wetterdienst weather data. You just need to create an account in the links provided. Hopefully, you will be able to use the data I provided. I've checked, it should be available in XML format. The ICON model should be in there.
https://werdis.dwd.de/werdis/start_js_JSP.do
https://kunden.dwd.de/gdsRegistration/gdsRegistrationStart.do