How Crowded Is Yellowstone National Park in September?

September runs about 2.1× Yellowstone National Park's average month, which makes it a very busy month here — roughly 17% of the park's yearly visitors come in September.

In a typical September the park sees about 742,000 recreation visits, based on National Park Service monthly counts from 1979 to 2025.

That makes September the 4th-busiest of the park's twelve months, sitting between the July peak (2.7×) and the November low (0.1×).

On our Best Time to Visit score September rates 34/100 ("Poor"), versus the top-rated April at 48/100 — best overall balance of crowds, weather and daylight.

Typical September weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 61°F and an overnight low around 30°F, with about 1.6" of precipitation.

That average of about 45°F is cool, so layers and a shorter daylight window matter.

Because June, July and August together draw about 61% of annual visitors, choosing September instead steps outside that summer crush — the single biggest lever on how crowded the park feels.

You'll have about 12.3 hours of daylight in September to explore — between the 8.6-hour midwinter low and the 15.4-hour summer high.

Park-wide, 2025 drew 4,762,988 recreation visits, about flat from 4,744,353 in 2024.

Across the past decade overall visitation has risen about 7.5%, so a September visit is likely to feel busier than it did a few years ago.