Glacier 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 Glacier National Park: crowds run 73% of the July peak (557,269 average visits), days average 63°F with 12.6 hours of daylight. Computed from NPS and NOAA data.
Crowds in September
Glacier averages 557,269 recreation visits in September — 73% of what July, the peak month, draws. Trailheads and parking fill accordingly — book early and start days at dawn.
Weather & daylight
Days are mild (highs average 63°F), and mornings are chilly (lows average 39°F). It is typically dry (1.6″ of precipitation). Mid-month daylight runs 12.6 hours.
NOAA 1991–2020 monthly normals, station ST. MARY 1 SSW, MT US (17 mi from park coordinates, 4,555 ft elevation) — conditions vary inside the park, especially with elevation. Daylight computed for the 15th of September.
What to pack for Glacier in September
Computed from the month's weather normals above — not a generic list.
- Warm mid-layer (fleece or light puffy) — mornings average 39°F
- 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)
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Also at their best in September
Other parks whose computed September verdict is a best window — same NPS × NOAA formula:
- Big Bend in September — 26% of peak crowds, highs 79°F, score 84/100
- 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
Common questions
Is Glacier crowded in September?
Yes — September runs 73% of Glacier's peak, averaging 557,269 recreation visits (NPS, 2021–2025).
What is the weather like in Glacier in September?
Average highs of 63°F, lows of 39°F, 1.6″ of precipitation (NOAA 1991–2020 normals, ST. MARY 1 SSW, MT US station).
What should I pack for Glacier in September?
Warm mid-layer (fleece or light puffy); Sturdy broken-in footwear, navigation and a basic first-aid kit; Bear spray — the full weather-computed list is on this page.
See also: the best national parks to visit in September · Last verified 2026-09-12