The Nemo Disco 15 sleeping bag is rated for use in temperatures as low as 15F or -9C. It has a comfort rating down to 25F or -4C. It is a warmer sleeping bag than the Disco 30 but not as warm as a zero degree bag like the Nemo Sonic 0. , The Nemo Disco is a very warm sleeping bag. It will accommodate temperatures down to 15F/-9C so it can be used for spring, summer and fall camping in most areas, and winter if you sleep in a location within the temperature rating. The draft collar and large hood also allow you to trap additional heat. This bag will keep you so warm and sleeping comfortably.