Mount Rainier in September: Crowds, Weather & What to Pack

Best window · VisitWhen score 68/100 · #3 of 12 months

September is one of the best months of the year to visit Mount Rainier National Park: crowds run 56% of the July peak (234,962 average visits). Weather: highs average 57°F and lows 41°F, with 4.4″ of precipitation and 12.6 hours of daylight. Computed from NPS and NOAA data.

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Crowds in September

Mount Rainier averages 234,962 recreation visits in September — 56% of what July, the peak month, draws. Trailheads and parking fill accordingly.

Weather & daylight

Days are cool (highs average 57°F), and mornings are chilly (lows average 41°F). This is one of the wetter months (4.4″ of precipitation on average). Mid-month daylight runs 12.6 hours.

NOAA 1991–2020 monthly normals, station RAINIER PARADISE RS, WA US (4 mi from park coordinates, 5,427 ft elevation) — conditions vary inside the park, especially with elevation. Daylight computed for the 15th of September.

What to pack for Mount Rainier in September

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

• Warm mid-layer (fleece or light puffy) — mornings average 41°F
• Rain shell + pack cover — 4.4″ of precipitation is normal this month
• Waterproof boots — plus navigation and a basic first-aid kit — 4.4″ of rain is normal this month

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Also at their best in September

Other parks whose computed September verdict is a best window — same NPS × NOAA formula:

• Wrangell–St. Elias in September — 25% of peak crowds, highs 56°F, score 84/100
• Guadalupe Mountains in September — 35% of peak crowds, highs 80°F, score 81/100
• Gateway Arch in September — 29% of peak crowds, highs 81°F, score 80/100
• Isle Royale in September — 39% of peak crowds, highs 65°F, score 79/100

Common questions

See also: the best national parks to visit in September · Last verified 2026-09-24