Mandan Weather in September

What's the weather like in Mandan (North Dakota) in September 2025?

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

September is in the fall / autumn in Mandan and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 22°C (71°F), whilst at night 6°C (43°F) is normal.

Mandan weather averages (imperial / metric)
Daytime temperature 21.5°C 70.6°F
Nightly temperature 6.4°C 43.4°F
Average temperature 13.9°C 57°F
Daily sunshine 8.9 hrs
Avg rainfall 37 mm 1.5 ins
Rainy days 7 days
Sea temperature 14.9°C 58.7°F
Humidity 64%
Windspeed 16.6kph 10 mph

On average September is the 6th wettest month of the year in Mandan with around 37mm 1.5 inches of rain making it a reasonably 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 8.9 hours of sunshine per day.

September temperatures in Mandan

Mandan average temperature in September

September rainfall

Mandan average rain in September

September hourly sunshine

Mandan 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 Mandan 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

Mandan weather stats

Mandan weather statistics
Hottest month: July 28.8°C 83.8°F
Driest month: February 9mm 0.4ins
Sunniest month: July 12.3hrs
Coldest month: January -6.8°C 19.8°F
Wettest month: June 81mm 3.2ins
Map showing location of Mandan (46.82666, -100.88958) Mandan map pin © Google

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