The weather in September in Washington

It's warm in September in Washington with an average temperature of 28°C. Temperatures this month range from a low of 25°C to a high of 31°C. At night, you can expect temperatures between 15°C and 22°C.

Looking for great weather? September is a good time to be in Washington. The temperatures are nice, and there’s not too much rain.

Average temperatures and precipitation

This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in September for Washington, United States. A low precipitation value usually indicates little to no rainfall on that day in recent years, while a higher value suggests more frequent rainfall.

Temperature records

With 39°C in 2023, Washington reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 16°C in 2022. The extreme nighttime temperatures ranged from a lowest recorded value of 4°C to a highest value of 26°C.

Rainfall amount

In September, there is an average of 59 mm of precipitation, spread over 10 days. The wind speed is around 4 Bft, mostly coming from the South.

Daily weather in September for Washington

Click on any day in September to get detailed info about the usual weather on that day in Washington. Check out the historical temperatures and precipitation over the past 10 years on this day.

September weather comparison

  Washington New York
Average temperature 28°C 27°C
Max. temperature 31°C 31°C
Min. temperature 15°C -5°C
Total precipitation 59 mm 57 mm
Rainy days 10 days 9 days

Start of September

The month of September starts in Washington with hot temps, averaging around 30°C during the day and nights around 21°C.

Mid September

By mid-September, daytime temps drop to around 29°C, with nights around 19°C. There’s a chance of some showers during this time, but plenty of dry and sunny days too.

End of September

By the end of September, the average daytime temperature in Washington is around 27°C, while nighttime temps are about 17°C. A shower might pop up, but overall, the weather will be dry and sunny.

UV index

The UV index is a maximum of 6 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.

Check out the climate of Washington for all months and discover the best travel time

The climate in Washington is based on weather data from . Other places, like New York City, Miami or Los Angeles, might have different weather. You can check out all destinations in Washington to get the full picture of the climate.

Temperature charts

These charts show the average temperatures in September in Washington, United States. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.

Daily Temperature in September in Washington

Temperature in September in Washington over the years

Precipitation charts

These charts show the average amount of precipitation in September in Washington, United States. Precipitation is always measured as water, even when it falls as snow or hail The amount of precipitation is displayed in millimeters, while snowfall is shown in centimeters.

Daily Precipitation in September in Washington

Total precipitation in September in Washington over the years

Daily UV index in September in Washington

This chart shows the average daily UV index in September in Washington, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.

Weather experiences in September in Washington

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Average weather in Washington by month

Click on a month below to see detailed weather info for Washington. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.