I'm having the same issue. I found there's an element called snowfallAmount when I debug the weather response, and the data in the snowfallAmount makes total sense. But the snowfallAmount is not available to use. Apple should make this element public and available to the developers.
You can see in the debug section, the variable contains the snowfallAmount element:
But when I want to use the snowfallAmount element in my code, the compiler complains it's not available:
@shiftingsand you can add my remarks including the images to explain to Apple about this omission.