Yellowstone in September: Crowds, Weather & What to Pack

Peak crowds · VisitWhen score 64/100 · #7 of 12 months

September is peak season — expect the year's biggest crowds at Yellowstone National Park: crowds run 86% of the July peak (796,027 average visits), days average 61°F with 12.6 hours of daylight. Computed from NPS and NOAA data.

Crowds in September

Yellowstone averages 796,027 recreation visits in September — 86% of what July, the peak month, draws. Plan lodging and entries with that in mind — book early and start days at dawn.

Weather & daylight

Daytime temperatures are comfortable (highs average 61°F), and nights drop below freezing (lows average 30°F). It is typically dry (1.6″ of precipitation). Mid-month daylight runs 12.6 hours.

NOAA 1991–2020 monthly normals, station YELLOWSTONE LAKE, WY US (6 mi from park coordinates, 7,835 ft elevation) — conditions vary inside the park, especially with elevation. Daylight computed for the 15th of September.

What to pack for Yellowstone in September

Computed from the month's weather normals above — not a generic list.

• Insulated jacket, beanie and gloves — nights average 30°F, below freezing
• Sturdy broken-in footwear, navigation and a basic first-aid kit — every park, every month
• Bear spray — recommended by the park in grizzly country (check current park regulations before you carry)

Looking for a better window? The computed best months for Yellowstone are April and May.

Common questions

See also: the best national parks to visit in September · Last verified 2026-07-16