My husband and I have been on the island for Aug and Sept for the last 10 years or so. A little quieter than in season but we like that aspect. Restaurants are open all of Aug. but many close for Sept. As Sail to Wind says it is a little bit hotter and humid, but not terrible. It is an island after all, and you get good breeze most of the time. It actually is one of our favorite times to be there.