It's even more weird when you realize that you can turn off visual displays of weather (and rivers!) in the settings menu despite the massive effects that both have on gameplay. The lack of a weather mapmode is a real shame considering how hard it can be to see them graphically, and no one wants to check every province tooltip in order to know where it's safe to attack. Honestly, you probably shouldn't even be able to turn off rivers. It's not like 3d trees or buildings where it doesn't matter if you can see them or not.
The best way to deal with weather in the current game is just to make sure all your tanks have 100%+ reliability and ignore it, which isn't very interactive.