Avg weather in September
12 Hrs per day
105 mm per month
74 % avg
6 Mph avg

Washington Weather in September

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What’s the weather like in Washington in September?

Washington, the capital of the United States, is an historic city in the east of the country. It has a climate that brings hot summers and cool winters to the region, as well as regular amounts of rainfall all year round. Temperatures are cooling down in September as the autumn approaches, but conditions are still warm at this time of year. For the hottest, sunniest weather, visit Washington closer to the start of September.


In September the average temperature in Washington is 22ºC, with highs of 27ºC in the height of the afternoon. At 17ºC, evenings are pleasant but you’ll need a jumper towards the end of the month if you plan on exploring the city after dark. Washington’s quite damp at this time of year, and with around 80mm of rain expected over the course of 11 days, it’s a good idea to bring a waterproof jacket or umbrella. The sun still shines for an average of eight hours each day though, so you should see some clear skies too.

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