Here in oklahoma it is not unusal to go from frosts to 90's. I try to give my cabbage, peas and other cool loving vegetables a misting with water in the heat of the afternoon on days that it gets especially hot for their liking. Of course I use various techniques to get the heat living plants out early to take advantage of the short period of optimal weather after the threat of frost is over. Stacking rocks around them to retain daytime heat is a favorite idea of mine. makes for big muscles too