I found the solution. If you have the same problem:
- Select the Forecast or OneCallApi in your model
- click on “create points from thing”
- select the corresponding thing
- select “unlinked channels”
- click “Show advanced”
- select the condition_ids and icon_ids you are missing
- click “Add To model”
Done
and read this: [OH3] Install & Set-up OpenWeatherMap via UI - #17 by murk_van_rooijen