Click on a day for an hourly weather forecast
The temperatures in Washington DC in September are comfortable with low of 18°C and and high up to 27°C.
You can expect about 3 to 8 days of rain in Washington DC during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Washington DC in September 2025.
If you’re planning to visit Washington DC in the near future, we highly recommend that you review the 14 day weather forecast for Washington DC before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 5° / -2° | 5 | 20 | 6 | 84 mm | Awful | Washington DC in January |
| February | 7° / -1° | 7 | 16 | 5 | 101 mm | Awful | Washington DC in February |
| March | 12° / 4° | 7 | 21 | 3 | 104 mm | Awful | Washington DC in March |
| April | 19° / 9° | 7 | 23 | 0 | 104 mm | Ok | Washington DC in April |
| May | 24° / 14° | 8 | 23 | 0 | 137 mm | Good | Washington DC in May |
| June | 29° / 19° | 6 | 24 | 0 | 126 mm | Good | Washington DC in June |
| July | 32° / 21° | 7 | 24 | 0 | 146 mm | Ok | Washington DC in July |
| August | 31° / 21° | 6 | 25 | 0 | 146 mm | Good | Washington DC in August |
| September | 27° / 18° | 5 | 25 | 0 | 119 mm | Perfect | Washington DC in September |
| October | 21° / 12° | 5 | 26 | 0 | 120 mm | Good | Washington DC in October |
| November | 13° / 5° | 4 | 26 | 0 | 79 mm | Ok | Washington DC in November |
| December | 8° / 2° | 6 | 22 | 3 | 104 mm | Bad | Washington DC in December |