Visiting local bars in Atiu is better when you know what the weather holds. These temperatures and rainfall averages can help you determine the best time for bar hopping. The hottest months are usually March and February with an average temp of 80°F, while the coldest months are August and September with an average of 75°F. The rainiest months in Atiu are January, March, December, and February, with each month seeing an average of 10 inches of rainfall.