If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Jaffna: The hottest months are usually April and May with an average temp of 84°F, while the coldest months are January and February with an average of 80°F. The rainiest months in Jaffna are November, December, October, and September, with each month seeing an average of 11 inches of rainfall.