Somalia has a tropical but not torrid climate, and there is little seasonal change in temperature. In the low areas, the mean temperature ranges from about 24° C to 31° C (75° to 88° F ). The plateau region is cooler, the southwest warmer. The periodic winds, the southwest monsoon (June–September), and the northeast monsoon (December–March) influence temperature and rainfall. Rain falls in two seasons of the year: heavy rains from March to May, and light rains from September to December. Average annual rainfall is estimated at less than 28 cm (11 in). Droughts are not infrequent.