Lying in the equatorial and tropical zone, Sri Lanka is influenced by the monsoons, allowing two distinct seasons: wet and dry. The difference of elevation also influences temperature variation; it is always hot in the lowland and it gets cooler when reaching the higher altitudes. The annually average temperature of the country as a whole varies from 26°C-28°C and dips down to 14°C-16°C in the Central Highlands. November to January is the coolest time of the year whereas February through May is the hottest period.
There are two monsoonal seasons in Sri Lanka, making its climate more complex and varied in different regions. In mid-May through October, the Southwest monsoon, called in Lankan language as “Yala season”, brings moisture from the Indian Ocean, resulting in the heavy rains in the south and west coasts as well as in the Central Highlands. Some windward slopes receive up to 250 centimeters of rain per month. In this period, the northern and eastern parts of the island are left drier with a little quantity of rainfall as lying in the lee-side.
When it comes to the Northeast monsoon (“Maha season” in Lankan) which lasts from December to March, the moisture brought from the Bay of Bengal causes downpours in the Northeast region of the island. The northeastern slopes of the mountains may be inundated with up to 125 centimeters of rains during these months.