AlbionWood,
In spring in central Illinois, "normal" is in the 20s to low 40s at night, 40s to low 90s daytime. Lots of wind though, I'm looking across miles of flat prairie surrounded by miles of flat prairie so the wind gets a good shot at me. Spring winds are often 15-25 mph and we had gusts to about 50 recently. The wasps and flies find shelter from the wind on the north and east sides of my house (where the doors are). Wetness varies a lot, some years it rains almost continuously and others it's fitful; average is 36 inches. In Spring it's often windy and drizzly, punctuated by occasional, massive downpours and tornadoes (just North of us last night). They are saying we might get snow here next week. No big deal. Soon the buffalo gnats will start hatching and we'll stop going outside for about a month.
Cornish Cross seem to handle the extreme variation in temperature very well but the gnats are deadly. We kept them in the brooder until they were 3 weeks old and well feathered then out into the cold, dark night they went. It gets windy enough here that we have to take precautions that the lids of the chicken tractors don't fly away. But the chickens themselves are performing very well in spite of cold, windy, wet nights.
Can't help you with the dry pasture problem. Seems like a chicken tractor passing over a piece of ground once/year would help more than hurt but don't really know your situation.