Temperature: Measuring range from 0°C to 50°C. In addition, the module is not tight. I operate the additional indoor module in a non-heated conservatory, and it has worked very well for 2 years. But it never gets below 0°C there.

I don't know the measuring range of the indoor module, however, it is not designed for outdoor operation in terms of sealing etc.. The outdoor module is basically available separately - at most not available at the moment...