I have the same issue on my iPad Air.
Tried unchecking the 7 day forcast but did not work.
The only way it will work is when i go ...
"Tools/Menue", Help.... If on the forum pages press map icon on top of screen.
The weather data then activates BUt only untill the "Done" button is pressed, then alas, back to dead grey world.
But I suspect that in this mode its like a mini web browser..