Manassas Weather in September

What's the weather like in Manassas (Virginia) in September 2025?

The climate in Manassas during September can be summarized as warm, humid and a little damp.

September is in the fall / autumn in Manassas and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a muggy 26°C (79°F), whilst at night 14°C (58°F) is normal.

Manassas weather averages (imperial / metric)
Daytime temperature 26.4°C 79.4°F
Nightly temperature 14.3°C 57.7°F
Average temperature 20.3°C 68.5°F
Daily sunshine 8 hrs
Avg rainfall 86 mm 3.4 ins
Rainy days 8 days
Sea temperature 22.1°C 71.7°F
Humidity 74%
Windspeed 11.5kph 7 mph

On average September is the 5th wettest month of the year in Manassas with around 86mm 3.4 inches of rain making it a a little damp time to visit. This rainfall is typically spread over 8 days, although this may vary considerably.

On the flip side this corresponds to an average of 8 hours of sunshine per day.

September temperatures in Manassas

Manassas average temperature in September

September rainfall

Manassas average rain in September

September hourly sunshine

Manassas 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 Manassas 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

Manassas weather stats

Manassas weather statistics
Hottest month: July 30.5°C 86.9°F
Driest month: January 69mm 2.7ins
Sunniest month: June 10.1hrs
Coldest month: January 5.3°C 41.5°F
Wettest month: August 100mm 3.9ins
Map showing location of Manassas (38.75095, -77.47527) Manassas map pin © Google

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