If you're looking forward to lots of outings with your partner, check out these details about year-round temperatures in Fernando de Noronha: The hottest months are usually April and May with an average temp of 81°F, while the coldest months are August and September with an average of 79°F. The rainiest months in Fernando de Noronha are April, March, May, and June, with each month seeing an average of 10 inches of rainfall.