I tried the SmartWool 250's this week during opening deer rifle season. I like them, as they are very warm. In fact, down to the 40's, I am comfortable wearing just the SmartWool 250 crew top with no jacket. In the 30's, I'll want to throw on a good jacket on top of the top layer, but I am very impressed with the performance of the SmartWool 250 gear. Plus wool wicks sweat and keeps you warm even if you get wet (in the rain, for example).