Temperatures in September
It's hot in September in Washington with an average temperature of 31°C. Temperatures this month range from a low of 28°C to a high of 34°C. At night, you can expect temperatures between 16°C and 23°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 33°C during the day and nights close to 22°C. A few showers might pop up in the first days of the month, but the weather remains mostly sunny and dry.
Mid-September
By mid-September, the average daytime temperature drops to around 31°C, with nights close to 20°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
Temperatures vary between day and night, so it’s smart to wear layers.
End of September
By the end of September, the average daytime temperature in Washington will be around 30°C, with nights close to 18°C. A shower might show up, but overall the weather will be dry and sunny.
As it gets cooler in the evening, it’s best to wear layers.
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Precipitation in September
In September, there is an average of 67 mm of precipitation, spread over 6 days. The wind speed is around 3 Bft, mostly coming from the Southeast.
The average precipitation chance is 21% per day this month. Though that seems low, there are also a few days with a higher chance of precipitation.
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 |
31°C | 20°C | |
 High Temp |
34°C | 22°C | |
| Low Temp |
28°C | 17°C | |
 Total Precipitation |
67 mm | 44 mm | |
| Rainy Days |
6 days | 8 days | |
August
UV index
The UV index is a maximum of 9 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.
Is September a good time to visit Washington?
September is a great month to be in Washington for sunny weather. You’ll get high temperatures and not too much rain this month.
Temperature records for Washington in September
With 38°C, Washington hit the highest temperature in the last 10 years in September 2019. The lowest daytime temperature in this month was 18°C in 2014. The extreme night temperatures ranged from a low of 8°C to a high of 25°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 6 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
Have you been to Washington in September?
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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
