Click on a day for an hourly weather forecast
The temperatures in Washington in September are comfortable with low of 11°C and and high up to 23°C.
You can expect about 3 to 8 days of rain in Washington 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 in September 2025.
If you’re planning to visit Washington in the near future, we highly recommend that you review the 14 day weather forecast for Washington before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 8° / 2° | 13 | 16 | 2 | 263 mm | Awful | Washington in January |
| February | 8° / 2° | 11 | 13 | 4 | 201 mm | Awful | Washington in February |
| March | 11° / 3° | 13 | 16 | 2 | 217 mm | Awful | Washington in March |
| April | 14° / 4° | 9 | 20 | 1 | 154 mm | Ok | Washington in April |
| May | 19° / 6° | 6 | 25 | 0 | 98 mm | Good | Washington in May |
| June | 22° / 9° | 4 | 26 | 0 | 84 mm | Good | Washington in June |
| July | 27° / 11° | 1 | 30 | 0 | 14 mm | Perfect | Washington in July |
| August | 27° / 12° | 1 | 30 | 0 | 20 mm | Perfect | Washington in August |
| September | 23° / 11° | 4 | 26 | 0 | 95 mm | Perfect | Washington in September |
| October | 16° / 8° | 9 | 22 | 0 | 201 mm | Ok | Washington in October |
| November | 10° / 4° | 13 | 17 | 1 | 222 mm | Bad | Washington in November |
| December | 7° / 1° | 12 | 17 | 2 | 261 mm | Awful | Washington in December |