If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Nuku’alofa: The hottest months are usually February and March with an average temp of 80°F, while the coldest months are August and September with an average of 73°F. The rainiest months in Nuku’alofa are February, March, January, and April, with each month seeing an average of 11 inches of rainfall.