Why is the climate in the north and south of Sri Lanka inconsistent?

Sri Lanka is an island country in the Indian Ocean, located at the southern tip of the South Asian subcontinent, facing the Indian Peninsula across the Pakistan Strait in the northwest.

Sri Lanka is close to the equator of the earth and belongs to the equatorial tropical climate affected by monsoon. The seasonal variation of temperature is small and the daily temperature difference is large. But there are still obvious differences between north and south. The climate in the north is savanna and the climate in the south is rainforest. The reasons are as follows: low latitude and high temperature; Affected by ocean currents, heated and humidified; Located on the windward slope of southwest monsoon and northeast monsoon, there is more precipitation. However, as far as the national climate characteristics are concerned, the average maximum temperature in coastal areas is 365,438 0.3℃, the average minimum temperature is 23.8℃, the average maximum temperature in mountainous areas is 26.65,438 0℃, and the average minimum temperature is 65,438 06.5℃. There are no four seasons, only the difference between rainy season and dry season. The rainy season is from May to August. 165433.