Click on a day for an hourly weather forecast
The temperatures in Saint Catharines in September are comfortable with low of 15°C and and high up to 22°C.
You can expect about 3 to 8 days of rain in Saint Catharines 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 Saint Catharines in September 2025.
If you’re planning to visit Saint Catharines in the near future, we highly recommend that you review the 14 day weather forecast for Saint Catharines before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -2° / -6° | 8 | 7 | 18 | 102 mm | Awful | Saint Catharines in January |
| February | -1° / -6° | 7 | 5 | 17 | 109 mm | Awful | Saint Catharines in February |
| March | 4° / -2° | 10 | 11 | 10 | 114 mm | Awful | Saint Catharines in March |
| April | 10° / 3° | 9 | 17 | 4 | 139 mm | Awful | Saint Catharines in April |
| May | 16° / 9° | 8 | 23 | 0 | 147 mm | Ok | Saint Catharines in May |
| June | 21° / 14° | 7 | 23 | 0 | 158 mm | Ok | Saint Catharines in June |
| July | 25° / 18° | 8 | 23 | 0 | 156 mm | Good | Saint Catharines in July |
| August | 25° / 19° | 7 | 24 | 0 | 148 mm | Good | Saint Catharines in August |
| September | 22° / 15° | 6 | 24 | 0 | 113 mm | Good | Saint Catharines in September |
| October | 15° / 10° | 9 | 22 | 1 | 135 mm | Ok | Saint Catharines in October |
| November | 8° / 3° | 8 | 16 | 6 | 95 mm | Awful | Saint Catharines in November |
| December | 2° / -1° | 9 | 8 | 15 | 109 mm | Awful | Saint Catharines in December |