Illustration of Earth showing it divided into the three climate zones. At the poles are the cold polar zones (blue). These are the areas that receive no sunlight during the winter solstice and 24 hours of sunlight during the summer solstice. Either side of the equator, the imaginary line (red) around the centre of the Earth, are the tropical zones. These extended to the Tropic of Cancer (upper green line) at 23.5 degrees north and the Tropic of Capricorn (lower green line) at 23.5 degrees south of the equator. In the tropical zones there are high temperatures and rainfall. Between the each Tropic and the polar zones are the temperate zones (green), which have lower temperatures and distinct seasons. For a labelled version of this image see C057/3729.