Acadia in September: Crowds, Weather & What to Pack
Peak crowds · VisitWhen score 60/100 · #9 of 12 months
September is peak season — expect the year's biggest crowds at Acadia National Park: crowds run 83% of the August peak (662,737 average visits), days average 71°F with 12.6 hours of daylight. Computed from NPS and NOAA data.
Crowds in September
Acadia averages 662,737 recreation visits in September — 83% of what August, 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 71°F), and nights stay mild (lows average 53°F). This is one of the wetter months (4.2″ of precipitation on average). Mid-month daylight runs 12.6 hours.
NOAA 1991–2020 monthly normals, station ACADIA NP, ME US (2 mi from park coordinates, 470 ft elevation) — conditions vary inside the park, especially with elevation. Daylight computed for the 15th of September.
What to pack for Acadia in September
Computed from the month's weather normals above — not a generic list.
- Rain shell + pack cover — 4.2″ of precipitation is normal this month
- Sturdy broken-in footwear, navigation and a basic first-aid kit — every park, every month
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Looking for a better window? The computed best months for Acadia are March and April.
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 Acadia crowded in September?
Yes — September runs 83% of Acadia's peak, averaging 662,737 recreation visits (NPS, 2021–2025).
What is the weather like in Acadia in September?
Average highs of 71°F, lows of 53°F, 4.2″ of precipitation (NOAA 1991–2020 normals, ACADIA NP, ME US station).
What should I pack for Acadia in September?
Rain shell + pack cover; Sturdy broken-in footwear, navigation and a basic first-aid kit — the full weather-computed list is on this page.
See also: the best national parks to visit in September · Last verified 2026-09-12