There are three major climate zones: tropical, temperate, and polar. Climate zones differ in temperature and precipitation. Tropical climates are usually warm and wet most of the year. Much of Central and South America are in the tropical climate zone. Temperate climates cycle through all four seasons — winter, spring, summer, and autumn. Much of the United States is in a temperate climate zone. Polar climates are usually cold and dry most of the year. Antarctica is in a polar climate zone.