If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Arugam Bay: The hottest months are usually June and July with an average temp of 84°F, while the coldest months are January and February with an average of 79°F. The rainiest months in Arugam Bay are December, November, January, and October, with each month seeing an average of 13 inches of rainfall.