How Crowded Is Acadia in September?
September is a very busy month at Acadia National Park, running about 2.0× the park's average month — roughly 17% of the year's visitors come in September. That puts it between the August peak and the February low. Overall our best-time score rates September as "Fair" for a visit. Typical September weather averages a high near 71°F and a low around 53°F, with about 4.2" of precipitation. You'll get about 12.3 hours of daylight to explore.
Frequently Asked Questions
September is very busy at Acadia National Park (about 2.0× the average month). Our best-time score rates it "Fair". The single best month overall is May.
The busiest month is August and the quietest is February. September sits at about 2.0× the park's average, or 17% of annual visitation.
Source: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-06-20.