This usually depends on the type of cot. Cots that have spring coils and foam mattresses are better at holding in body heat. The downside about these types of cots is that the materials are very porous and hold moisture which can make them become cold and uncomfortable. The cots composed of nylon or canvas materials typically require campers to reach for extra blankets, especially on cold nights. However, they are great with wicking away water and moisture to keep campers dry.