Well, it kept me warm through pretty much every type of weather while hiking the AT for a month so I feel I owe this little guy at least four stars. It's a bit clammy to sleep in (but I suppose all bags are??), but it makes up for it by keeping you warm and dry. If it gets a bit damp from rubbing against a tent wall or being dusted with rain while in a shelter, it dries quickly. Luckily I never got it very wet, so I am not sure how it responds to that. I am generally a very cold person when I sleep, but this one kept me warm so I recommend it to anyone who is generally cold while sleeping. My coldest night in it was about 20 degrees with a wind chill probbaly in the lower teens...and even then, it was great.