How Crowded Is Yellowstone in September?
September is a very busy month at Yellowstone National Park, running about 2.1× the park's average month — roughly 17% of the year's visitors come in September. That puts it between the July peak and the November low. Overall our best-time score rates September as "Poor" for a visit. Typical September weather averages a high near 61°F and a low around 30°F, with about 1.6" of precipitation. You'll get about 12.3 hours of daylight to explore.
Frequently Asked Questions
September is very busy at Yellowstone National Park (about 2.1× the average month). Our best-time score rates it "Poor". The single best month overall is April.
The busiest month is July and the quietest is November. September sits at about 2.1× 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.