Latitude is a measure of distance from the equator. Locations between the Tropic of Cancer and the Tropic of Capricorn, between 23 degrees north and 23 degrees south latitude, are considered tropical. As you move away from the equator, climates shift incrementally through subtropical, temperate, subarctic, and, finally, arctic at the poles. The tilt of the Earth on its axis means that the further you get from the equator, the longer the area spends tilted away from the sun each year, and the cooler and more seasonal the climate.