A tropical climate is a climate of the tropics. In the Köppen climate classification it is a non-arid climate in which all twelve months have mean temperatures above 18 °C (64 °F). Unlike the extra-tropics, where there are strong variations in day length and temperature, with season, tropical temperature remains relatively constant throughout the year and seasonal variations are dominated by precipitation.
Within the tropical climate zone there are distinct varieties based on precipitation:
Note that, in this scheme, many places within the tropics do not have a tropical climate: for example, the Sahara desert. Mountaintops within the tropics, e.g. Mount Kenya, can be cold.
Because of the effect of sun angle on climate most areas within the tropics are hot year-round, with diurnal variations in temperature exceeding seasonal variations. Seasonal variations in tropical climate are dominated by changes in precipitation, which are in turn largely influenced by the tropical rain belt or Intertropical Convergence Zone (ITCZ), a portion of the Hadley cell. The ITCZ is shown, for July average, in the graphic. Areas of ascending air have heavy rainfall; areas of descending air are dry. The ITCZ somewhat follows the solar equator throughout the year, but with geographical variations, and in some areas (India) is heavily influenced by local large-scale monsoons.