Temperatures in September
It's warm in September in Washington with an average temperature of 24°C. Temperatures this month range from a low of 21°C to a high of 29°C. At night, you can expect temperatures between 7°C and 17°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Washington in September. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of September
The month of September starts in Washington with hot temperatures, averaging around 27°C during the day and nights close to 16°C. You can expect regular precipitation, but there’s also a chance for some sunny days in the first days of the month.
Since temperatures can differ between day and night, it’s a good idea to dress in layers.
Mid-September
By mid-September, the average daytime temperature drops to around 24°C, with nights close to 12°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
End of September
By the end of September, the average daytime temperature in Washington will be around 24°C, with nights close to 11°C. A shower might show up, but overall the weather will be dry and sunny.
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Precipitation in September
In September, there is an average of 89 mm of precipitation, spread over 8 days. The wind speed is around 3 Bft, mostly coming from the South.
The average precipitation chance is 26% per day this month. Though it seems pretty low, the weather’s variable. Some days have higher and others lower precipitation chances, which lowers the average.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in September for Washington. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Washington in September |
London | ||
|---|---|---|---|
 Average Temperature |
24°C | 20°C | |
 High Temp |
29°C | 22°C | |
| Low Temp |
21°C | 17°C | |
 Total Precipitation |
89 mm | 44 mm | |
| Rainy Days |
8 days | 8 days | |
August
UV index
The UV index is a maximum of 5 this month. That's a moderate value on the intensity scale of 1 to 11. Unprotected skin can burn in about 30 minutes.
Is September a good time to visit Washington?
Want nice weather? Then September is a great time to be in Washington. You’ll have pleasant temperatures and not too much rain this month.
Temperature records for Washington in September
With 34°C, Washington hit the highest temperature in the last 10 years in September 2018. The lowest daytime temperature in this month was 13°C in 2022. The extreme night temperatures ranged from a low of 0°C to a high of 22°C.
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Daily Temperature in September in Washington
This chart shows the average daily temperatures, both day and night, for each day in September in Washington, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in September in Washington
The chart below shows the average daily precipitation in September for Washington, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for September, you can expect around 8 days of rain in Washington.
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.
Temperature in September in Washington Over the Years
This chart shows the average temperature in September in Washington, measured in degrees Celsius, over the past years.
Total Precipitation in September in Washington Over the Years
This chart shows the average precipitation in September in Washington, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in September for Washington
Click on a specific day in September for detailed info on the typical weather on that day in Washington. Check out the historical temperatures and precipitation over the past 10 years on this day.
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.
Or check out the climate of Washington for all months at once
