Cambodia’s climate is governed by the monsoon winds, which define two major seasons. From mid-May to early October, the strong prevailing winds of the southwest monsoon bring heavy rains and high humidity. From early November to mid-March, the lighter and drier winds of the northeast monsoon bring variable cloudiness, infrequent precipitation, and lower humidity. The weather between these seasons is transitional. Maximum temperatures are high throughout the year, ranging from about 82 to 83 °F (28 °C) in January, the coolest month, to about 95 °F (35 °C) in April. Annual precipitation varies considerably throughout the country, from more than 200 inches (5,000 mm) on the seaward slopes of the southwestern highlands to about 50–55 inches (1,270–1,400 mm) in the central lowland region. Three-fourths of the annual rainfall occurs during the months of the southwest monsoon.