Click on a day for an hourly weather forecast
The temperatures in Brockville in September are comfortable with low of 11°C and and high up to 21°C.
You can expect about 3 to 8 days of rain in Brockville 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 Brockville in September 2025.
If you’re planning to visit Brockville in the near future, we highly recommend that you review the 14 day weather forecast for Brockville before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -5° / -12° | 5 | 6 | 21 | 91 mm | Awful | Brockville in January |
| February | -4° / -11° | 5 | 4 | 20 | 104 mm | Awful | Brockville in February |
| March | 3° / -5° | 8 | 8 | 15 | 86 mm | Awful | Brockville in March |
| April | 10° / 2° | 10 | 15 | 5 | 136 mm | Awful | Brockville in April |
| May | 18° / 8° | 8 | 22 | 1 | 133 mm | Ok | Brockville in May |
| June | 22° / 12° | 7 | 23 | 0 | 131 mm | Ok | Brockville in June |
| July | 26° / 15° | 7 | 24 | 0 | 130 mm | Good | Brockville in July |
| August | 25° / 15° | 6 | 25 | 0 | 138 mm | Perfect | Brockville in August |
| September | 21° / 11° | 5 | 25 | 0 | 103 mm | Good | Brockville in September |
| October | 14° / 6° | 8 | 22 | 1 | 125 mm | Ok | Brockville in October |
| November | 6° / -1° | 6 | 17 | 8 | 78 mm | Awful | Brockville in November |
| December | -1° / -6° | 8 | 7 | 17 | 105 mm | Awful | Brockville in December |