Washington, D. C. Weather in September

What's the weather like in Washington, D. C. (Washington, D.C.) in September 2025?

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

September is in the fall / autumn in Washington, D. C. and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a muggy 26°C (79°F), whilst at night 15°C (60°F) is normal.

Washington, D. C. weather averages (imperial / metric)
Daytime temperature 26.3°C 79.3°F
Nightly temperature 15.4°C 59.6°F
Average temperature 20.8°C 69.4°F
Daily sunshine 8 hrs
Avg rainfall 87 mm 3.4 ins
Rainy days 8 days
Sea temperature 22.1°C 71.7°F
Humidity 72%
Windspeed 12.6kph 8 mph

On average September is the 5th wettest month of the year in Washington, D. C. with around 87mm 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 Washington, D. C.

Washington, D. C. average temperature in September

September rainfall

Washington, D. C. average rain in September

September hourly sunshine

Washington, D. C. 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 Washington, D. C. 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

Washington, D. C. weather stats

Washington, D. C. weather statistics
Hottest month: July 30.5°C 86.9°F
Driest month: February 70mm 2.8ins
Sunniest month: June 10hrs
Coldest month: January 4.9°C 40.8°F
Wettest month: August 103mm 4.1ins
Map showing location of Washington, D. C. (38.89511, -77.03637) Washington, D. C. map pin © Google

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