Climate zones are defined as the condition of the atmosphere at a particular location over a long period of time. Sri lanka has tropical climate. Middle of the country is significant cool as well as other areas are quite hot. The average yearly temperature for the country as a whole ranges from 28 to 30 °C (82.4 to 86.0 °F).

In sri lanka, January classified as a coolest month in highlands and May is warmest. The mean annual temperature varies from 27°C in the coastal lowlands to 16°C at NuwaraEliya, in the central highlands (1900m above mean sea level). This relatively unique feature manifesting as sunny beaches to rain forests inland is a tourist attraction. The mean monthly temperatures differs slightly depending on the seasonal movement of the sun, with some modified influence caused by rainfall.

The rainiest areas are the south-western mountain slope and the coastal area where Colombo is located. There are two peaks in the rainfall. The first is, 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.

In the north-west, Temperatures are high throughout the year, but compared to the south, there’s a greater difference between the pre-monsoon period. In Nuwara Eliya, 1,900 mm (75 in) of rain fall per year and the rainfall pattern is similar to that of Kandy. However, there is no real dry season, although in January, February and March, the rains are around 70/100 mm (2.8/4 in) per month. Humidity is typically higher in the southwest and mountainous areas and depends on the seasonal patterns of rainfall.

In mountainous areas, cloudiness is more common, and the sun can be seen rarely from May to December. The Climate zones experienced during 12 months period in Sri Lanka can be characterized in to 4 climate seasons. First-inter monsoon period, Southwest monsoon season, Second-inter monsoon season and Northeast monsoon season.