Unlike many other Asian destinations, Sri Lanka can lay genuine claim to being a year-round holiday destination. You just have to know which side of the island to focus on in any given month, and this is never more important than when planning your beach destination.
Unquestionably, the starting point when planning your trip in Sri Lanka is understanding the two monsoon seasons. 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 drier 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.
Whilst planning any holiday around the seasons, it’s important to remember that the world’s weather has a funny habit of not sticking to script, and this is never truer than in Sri Lanka. You will often be blessed with clear blue skies in what should be rainy season, or with torrential downpours in the middle of the dry season. Therefore you would do well to consider a whole host of other elements (ie seasonal airfares,school holidays etc) in addition to the weather when making your plans.
In general when it does rain, it’s unusual for the rain to last all day, with downpours tending to be short and sharp, often with a number of inches falling in just a matter of minutes. In extreme cases this can lead to localised flooding, which when severe can require last minute alterations to your travel plans... one of the highlights of travelling in Asia!
Relative humidity in Sri Lanka typically ranges from 60% - 90% and is generally higher in the south-west and mountainous areas, although it is also effected by seasonal patterns and rainfall. While Colombo can experience year-round daytime humidity in excess of 70% (rising to approximately 90% during the monsoon season), humidity in the Cultural Triangle drops as low as 60% during the monsoon month of March, and peaks at around 80% during the November and December rains. In the highlands, Kandy's daytime humidity usually ranges between 70% and 80% throughout the year.