The central plateau enjoys pleasantly cool weather, with an average temperature of 20 °C (68 °F). The area around Lake Tanganyika is warmer, averaging 23 °C (73.4 °F); the highest mountain areas are cooler, averaging 16 °C (60.8 °F).
Bujumbura’s average annual temperature is 23 °C (73.4 °F). Rain is irregular, falling most heavily in the northwest. Dry seasons vary in length, and there are sometimes long periods of drought.
However, four seasons can be distinguished: the long dry season (June–August), the short wet season (September–November), the short dry season (December–January), and the long wet season (February–May).
Most of Burundi receives between 1,300 and 1,600 mm (51.2 and 63.0 in) of rainfall a year. The Ruzizi Plain and the northeast receive between 750 and 1,000 mm (29.5 and 39.4 in).