Does mid-air refueling have very hard constraints on weather?
The receiver has to have visual contact with the tanker to complete the rejoin, so finding a clear block of airspace (i.e. not IMC) is necessary. Beyond that, none of the factors mentioned really matter much.  Turbulence can make refueling more difficult, although it's often possible to find an altitude with a decent ride.

Mostly, AR can be done; the times when it can't are much more the exception.