Page "Geography of Sri Lanka" Paragraph 13

The rainfall pattern is influenced by the monsoon winds of the Indian Ocean and Bay of Bengal and is marked by four seasons.

The first is from mid-May to October, when winds originate in the southwest, bringing moisture from the Indian Ocean.

When these winds encounter the slopes of the Central Highlands, they unload heavy rains on the mountain slopes and the southwestern sector of the island.

Some of the windward slopes receive up to of rain per month, but the leeward slopes in the east and northeast receive little rain.

The second season occurs in October and November, the intermonsoonal months.

During this season, periodic squalls occur and sometimes tropical cyclones bring overcast skies and rains to the southwest, northeast, and eastern parts of the island.

During the third season, December to March, monsoon winds come from the northeast, bringing moisture from the Bay of Bengal.

The northeastern slopes of the mountains may be inundated with up to of rain during these months.

Another intermonsoonal period occurs from March until mid-May, with light, variable winds and evening thundershowers.