Click on a day for an hourly weather forecast
The temperatures in Mount Vernon in September are comfortable with low of 17°C and and high up to 25°C.
You can expect about 3 to 8 days of rain in Mount Vernon 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 Mount Vernon in September 2025.
If you’re planning to visit Mount Vernon in the near future, we highly recommend that you review the 14 day weather forecast for Mount Vernon before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 2° / -3° | 5 | 18 | 8 | 101 mm | Awful | Mount Vernon in January |
| February | 4° / -3° | 6 | 13 | 9 | 120 mm | Awful | Mount Vernon in February |
| March | 8° / 2° | 7 | 19 | 5 | 133 mm | Awful | Mount Vernon in March |
| April | 14° / 7° | 8 | 22 | 1 | 128 mm | Ok | Mount Vernon in April |
| May | 20° / 12° | 8 | 23 | 0 | 141 mm | Ok | Mount Vernon in May |
| June | 26° / 17° | 7 | 23 | 0 | 152 mm | Good | Mount Vernon in June |
| July | 29° / 21° | 10 | 21 | 0 | 202 mm | Ok | Mount Vernon in July |
| August | 29° / 21° | 7 | 24 | 0 | 189 mm | Ok | Mount Vernon in August |
| September | 25° / 17° | 5 | 25 | 0 | 132 mm | Perfect | Mount Vernon in September |
| October | 18° / 12° | 6 | 25 | 0 | 147 mm | Good | Mount Vernon in October |
| November | 11° / 5° | 5 | 24 | 1 | 96 mm | Ok | Mount Vernon in November |
| December | 6° / 1° | 7 | 19 | 5 | 151 mm | Awful | Mount Vernon in December |