Weather will likely play an important role when you plan your trip to Kalutara, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually March and April with an average temp of 82°F, while the coldest months are January and February with an average of 80°F. The rainiest months in Kalutara are May, June, October, and November, with each month seeing an average of 16 inches of rainfall.