This is a Grrrrreat jacket. I bought one last year before an end of January Mountaineering trip on the Eastern side of the Sierras. The weather was very windy and in the teens and the OR Incandescent Hoody kept my core warm the entire time. I wore it by itself as well as under my Arcteryx shell. Also, the hood fit perfect under my Petzl helmet and added a whole lot more warmth. FYI, it's a slim fit around the hips. Great buy.