Sri Lanka has a tropical climate.
The central part of the southern half of the island is mountainous with heights more than 2.5 Km. The core regions of the central highlands contain many complex topographical features such as ridges, peaks, plateaus, basins, valleys and escarpments. The remainder of the island is practically flat except for several small hills that rise abruptly in the lowlands. These topographical features strongly affect the spatial patterns of winds, seasonal rainfall, temperature, relative humidity and other climatic elements, particularly during the monsoon season.
The south-western monsoon brings rain to the south-west of Sri Lanka between May and September, while the dry season in this region runs from December to March.
In the north and eastern coastal regions of the country, the weather is influenced by the north-eastern monsoon, which brings wind and rain between October and January, and dryer weather between May and September.
There is also an inter-monsoonal period during October and the first half of November, when rain and thunderstorms can occur across the island. This clears up as December nears, with conditions getting balmier by the day during the second half of November.
As with many South-East Asian destinations, the period from December to mid-April is considered the peak season for overall weather and therefore overall visitor numbers. Whilst there is good reason for this, there are equal benefits to travelling outside of this period, with the shoulder season often providing the best of both worlds; namely great weather and a lower visitor numbers.