Went camping for the first time and (at least on the hike) didn't even need a jacket despite mid-20s temperatures. Of course, when I got above the tree line I donned a shell, but this base layer blew me away. Even if it makes me sweat, it somehow keeps me warm! Also, I went camping the next day but accidentally left this in my car overnight - a solid block of ice. Whoops - 20 mins on my center vent with the best turn on and was good to go :) 5'6" and 185 - athletic build - large size will be ordering another one soon.