Since delivery, for some COMPLETELY UNEXPLAINABLE reason, the InControl Touch Pro Weather Live app used Fahrenheit on the side panel but Celsius when displayed full screen on a 2017 Range Rover.
My preference for Fahrenheit is chosen everywhere I could find prior to today. The InControl website account, the car itself, and a few other places all set for Fahrenheit. And as shown, it works fine for the side panel.
But the key for the fix that I found today while checking out another feature is simple (And apparently undocumented?)
Bring up the full screen Weather Live app then tap the Settings button (small double gear icon) then Weather Settings then configure from there. A few taps and all is fixed.
As I found, hitting that Settings button on every screen and then going into the contextual settings for the function displayed has helped find some things previously hidden to me.