Many parts of the world experience higher rates of mortality and morbidity during winter months than at other times of the year. Much of this wintertime excess is caused by exposure to weather factors, in particular, low ambient temperatures. Most health impacts occur as a result of cardiorespiratory problems rather than directly due to hypothermia. Elderly people are most at risk. A large fraction of cold-related health impacts can be avoided by taking appropriate adaptation measures such as warmer housing. Intervention measures designed to minimize cold exposure and reduce fuel poverty will likely play a key role in determining current and future health burdens of cold weather.