Dillon Weather in September

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

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

September is in the fall / autumn in Dillon and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 21°C (70°F), whilst at night 4°C (38°F) is normal.

Dillon weather averages (imperial / metric)
Daytime temperature 21.1°C 69.9°F
Nightly temperature 3.6°C 38.4°F
Average temperature 12.3°C 54.1°F
Daily sunshine 9.7 hrs
Avg rainfall 26 mm 1 ins
Rainy days 7 days
Sea temperature 14.2°C 57.5°F
Humidity 54%
Windspeed 13.7kph 9 mph

On average September is the 5th wettest month of the year in Dillon with around 26mm 1 inches of rain making it a dry time to visit. This rainfall is typically spread over 7 days, although this may vary considerably.

On the flip side this corresponds to an average of 9.7 hours of sunshine per day.

September temperatures in Dillon

Dillon average temperature in September

September rainfall

Dillon average rain in September

September hourly sunshine

Dillon 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 Dillon 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

Dillon weather stats

Dillon weather statistics
Hottest month: July 28°C 82.4°F
Driest month: February 6mm 0.2ins
Sunniest month: July 13hrs
Coldest month: January -0°C 32°F
Wettest month: June 53mm 2.1ins
Map showing location of Dillon (45.21631, -112.63752) Dillon map pin © Google

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