Click on a day for an hourly weather forecast
The temperatures in Orillia in September are usually low and can range between 11°C and 20°C.
You can expect about 3 to 8 days of rain in Orillia 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 Orillia in September 2025.
If you’re planning to visit Orillia in the near future, we highly recommend that you review the 14 day weather forecast for Orillia before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -5° / -12° | 6 | 3 | 24 | 105 mm | Awful | Orillia in January |
| February | -4° / -11° | 5 | 2 | 22 | 91 mm | Awful | Orillia in February |
| March | 2° / -5° | 8 | 8 | 16 | 95 mm | Awful | Orillia in March |
| April | 9° / 1° | 9 | 12 | 8 | 135 mm | Awful | Orillia in April |
| May | 17° / 7° | 8 | 22 | 1 | 122 mm | Ok | Orillia in May |
| June | 21° / 11° | 8 | 22 | 0 | 136 mm | Ok | Orillia in June |
| July | 24° / 15° | 7 | 24 | 0 | 138 mm | Good | Orillia in July |
| August | 24° / 15° | 6 | 25 | 0 | 144 mm | Perfect | Orillia in August |
| September | 20° / 11° | 6 | 24 | 0 | 107 mm | Good | Orillia in September |
| October | 13° / 6° | 9 | 21 | 2 | 138 mm | Awful | Orillia in October |
| November | 5° / 0° | 8 | 11 | 11 | 101 mm | Awful | Orillia in November |
| December | -1° / -6° | 7 | 4 | 21 | 109 mm | Awful | Orillia in December |