Description lists partial insulation. Its rather light so a base layer would be beneficial on those really cold days. On the other hand, my Volcom pants with just butt and knee insulation work like a charm in the low low temps. These pants could also use a left side pocket. If you carry a lot of gear in your pants, you may want to look elsewhere. But the fit is good (not too baggy, not to slim) and color is sweet. Apple green is not as bright in main picture, more like the detail pics.