Located in the tropical zone, El Salvador has two distinct seasons: the dry season, from November to April, when light rains occur, and the wet season, from May to October, when the temporales , or heavy rains, fall. The coastal plain receives the heaviest rainfall. Some interior areas are relatively dry most of the year, necessitating irrigation and a selection of crops suited for arid land cultivation. The average annual rainfall is 182 cm (72 in). Temperatures vary with altitude, from the hot coastal lowlands to the semitropical central plateau; in general, the climate is warm, with an annual average maximum of 32° C (90° F ) and an average minimum of 18° C (64° F ). The average temperature at San Salvador is 22° C (72° F ) in January and 23° C (73° F ) in July.