Washington Weather in September

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

September is in the fall / autumn in Washington and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 24°C (75°F), whilst at night 12°C (53°F) is normal.

On average September is the 6th driest month of the year in Washington with around 79mm 3.1 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 10 days, although this may vary considerably.

On the flip side this corresponds to an average of 6.9 hours of sunshine per day.

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 in September 2024.