Chinook Weather in September

What's the weather like in Chinook (Montana) in September 2025?

The climate in Chinook during September can be summarized as mild and reasonably dry.

September is in the fall / autumn in Chinook and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 22°C (71°F), whilst at night 5°C (40°F) is normal.

Chinook weather averages (imperial / metric)
Daytime temperature 21.6°C 70.8°F
Nightly temperature 4.7°C 40.4°F
Average temperature 13.1°C 55.6°F
Daily sunshine 9.3 hrs
Avg rainfall 34 mm 1.3 ins
Rainy days 5 days
Sea temperature 13°C 55.4°F
Humidity 56%
Windspeed 17.6kph 11 mph

On average September is the 4th wettest month of the year in Chinook with around 34mm 1.3 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 5 days, although this may vary considerably.

On the flip side this corresponds to an average of 9.3 hours of sunshine per day.

September temperatures in Chinook

Chinook average temperature in September

September rainfall

Chinook average rain in September

September hourly sunshine

Chinook average rain in September

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Chinook in September 2025.

Other monthly averages

Best places to visit in September

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Chinook weather stats

Chinook weather statistics
Hottest month: July 29.1°C 84.4°F
Driest month: February 9mm 0.4ins
Sunniest month: July 13.6hrs
Coldest month: January -4.9°C 23.2°F
Wettest month: June 57mm 2.2ins
Map showing location of Chinook (48.59, -109.23128) Chinook map pin © Google

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