In Sri Lanka the climate is tropical, hot and humid throughout the year (in fact, the country is located just north of the equator), and affected by the monsoon regime, which influences the rainfall pattern. In addition, the inland elevations, which are higher in the south-central part of the island, influence the intensity and the distribution of rainfall in the different areas: the south-western mountain slope and the coastal area of the capital Colombo are the rainiest, while the driest areas are the north-west coast and south-east coast.

The rains in Sri Lanka, as usually happens in countries having a tropical climate, occur mainly in the form of downpour or a thunderstorm. There are two peaks in the rainfall: the first, in April and May, only affects the south-west and the interior, while the second, from October to December, due to the retreating monsoon, affects the whole country. During summer, the southwest monsoon prevails, but it releases the bulk of the rains in India, and in Sri Lanka it brings heavy rains only on the southwest coast and in the mountainous interior.

From March to May, before the arrival of the monsoon, there is an increase in temperature, more noticeable in the north-central part of the country. The amount of sunshine is never low on the coasts, because even in summer and during the rainy autumn season there are on average about 6 hours of sunshine a day, however, it is better in the dry season (January to March in Colombo and on the west coast, and February to April in Batticaloa and on the east coast), when there are 8/9 hours of sunshine per day. On the contrary, in inland mountainous areas, cloudiness is more common, and the sun is rarely seen from May to December.