You guys do realize that in WWII if the weather was bad or even marginal they often times didn't fly at all???
WWII Fighter Pilot "Is it raining today?
Weather Guesser "Why yes it is."
WWII Fighter Pilot "All right then, guess I'll go over to the O Club for a beer."
Weather Guesser "Yep I'll be over there shortly myself."
WWII Fighter Pilot "How's tomorrow look?"
Weather Guesser "Maybe it'll clear up but not sure yet. Save me a seat at the bar will ya?"
WWII Bomber Pilot "Hows the weather over the target area?"
Weather Guesser "Looks to be heavy overcast with some rain."
WWII Bomber Pilot "O well, I guess we'll try again tomorrow."
Weather Guesser "Sounds good, save me a seat at the bar will ya?"
You guys see the trend here? WWII aircraft were FAIR weather aircraft. If the weather was crappy they stayed on the ground. Why do you think airpower didn't factor into the Battle of the Bulge? Because the weather was crappy and the planes couldn't fly.
So no we don't need weather because it's not realistic to have it. Changing seasons I could see, and it would be kinda neat to see the trees changing colors and stuff, snow on the ground and all, but actual precipitation, nope don't need it.