As JB said, it varies. What kind of plane are you flying, a CE-208 or a 747? And where? SoCal doesn't know the definition of winter. Detroit is a whole different story. Years ago I was talking to YIP operator looking for Convair check airmen. They also operated DC-6s. They said I could fly the Six but I would have to spend a winter as an FO. Made a lot of sense.