Nice and warm. In fact, I'm able to downsize the baselayer I use with these unless it's REALLY cold outside. It's my go-to choice when the temps are down, down down and I know I need to bundle up.And my drawback is half a joke, but seriously: With most baselayers, it feels like you work up enough static to light a building. That's just going to be a drawback of just about any article of clothing, though. When it's cold enough, there's no avoiding it. It's a fair trade. I'm warm while I'm wearing it (wearing it right now, in fact, on a below-zero wind-chill day outside), and that's what matters.