Napoleon Weather in September

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

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

September is in the fall / autumn in Napoleon and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 21°C (70°F), whilst at night 6°C (42°F) is normal.

Napoleon weather averages (imperial / metric)
Daytime temperature 21°C 69.8°F
Nightly temperature 5.8°C 42.4°F
Average temperature 13.4°C 56.1°F
Daily sunshine 8.6 hrs
Avg rainfall 45 mm 1.8 ins
Rainy days 7 days
Sea temperature 15°C 58.9°F
Humidity 65%
Windspeed 17.3kph 11 mph

On average September is the 5th wettest month of the year in Napoleon with around 45mm 1.8 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 8.6 hours of sunshine per day.

September temperatures in Napoleon

Napoleon average temperature in September

September rainfall

Napoleon average rain in September

September hourly sunshine

Napoleon 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 Napoleon 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

Napoleon weather stats

Napoleon weather statistics
Hottest month: July 28.3°C 82.9°F
Driest month: February 11mm 0.4ins
Sunniest month: July 12.1hrs
Coldest month: January -8.6°C 16.5°F
Wettest month: June 80mm 3.1ins
Map showing location of Napoleon (46.50831, -99.77122) Napoleon map pin © Google

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