If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Bentota: 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 Bentota are May, June, October, and November, with each month seeing an average of 16 inches of rainfall.