Katmai National Park weather in September

September in Katmai National Park: cool, rainy, with clean air — a great time to visit.

#5 of 12 months in Katmai National Park · #376 of 604 destinations to visit in September · comfort 75/100 (tier B)

Updated June 2026 · climate normals from ERA5 reanalysis

Katmai National Park climate normals — September

Daytime high12°C / 53°F🙂 cool
Nighttime low6°C / 44°F
Feels like (high)10°C / 50°F
Rainfall148 mm / 5.8 in🌧 rainy
Rainy days18 days
Humidity87%💦 very humid
Dew point6°C / 43°F
Sunshine6 h/day
Daylight12.8 h
Wind10 km/h / 6 mph
Snowfall6.9 cm / 2.7 in
Air quality (US AQI)24🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Where is Katmai National Park?

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Katmai National Park in September — FAQ

Is September a good time to visit Katmai National Park?
September in Katmai National Park: cool, rainy, with clean air — a great time to visit. It ranks #5 of 12 months for Katmai National Park on SeasonMap's comfort score (75/100).
What is the weather like in Katmai National Park in September?
In September, Katmai National Park averages a daily high of 11.5°C and a low of 6.4°C, with about 148.1 mm of rain over roughly 18.2 rainy days.
What is the air quality in Katmai National Park in September?
Katmai National Park has a mean US Air Quality Index of about 24 in September.
Does it snow in Katmai National Park in September?
Katmai National Park sees roughly 6.9 cm of snowfall in September.

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