This paper will analyze the effects of warmer temperature on diseases spread by insects, mortality caused by extreme temperatures, and how premature deaths generally are related to climate. The models and record to date suggest that global warming will boost temperatures most in the winter and at night and have only a modest effect on summer heat. By itself this should benefit, not harm Americans. More people die of cold than warmth and more die during the winter than during the summer, thus suggesting that a warmer climate will have beneficial effects of life expectancies. During the first half of this century and in the nineteenth century many so called tropical diseases such as Malaria and Cholera were endemic in the United States. Modern sanitation, not a cooling in the climate, rid our nation of these afflictions. It is currently warmer in the states along the Gulf of Mexico than on Caribbean islands, but the latter suffer from dengue fever while these warm portions of the U.S. are free from that malady. My own research shows that people in the United States who live in warm areas have lower mortality rates, after adjusting for age, income, and race than people in colder climes.