The skin is important in preserving homeostasis between man and his environment. One main role of the skin is in thermoregulation, where cutaneous blood flow, and hence skin temperature, vary widely in order to help preserve core body temperature. Under extreme conditions, frostbite or bums may occur. Prolonged exposure to moderate degrees of heat or cold can result in erythema ab igne and chilblains. Temperature plays a direct role in some of the physical urticarias and is one of several important pathogenic factors in conditions such as Raynaud’s syndrome, cold panniculitis, and cryoglobulinemia. These and other temperature-dependent skin disorders are reviewed.