The temperatures in Ontario 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 Ontario 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 Ontario in September 2025.
If you’re planning to visit Ontario in the near future, we highly recommend that you review the 14 day weather forecast for Ontario before you arrive.
Temperatures
22° / 15°
Rainy Days
5
Snowy Days
0
Dry Days
25
Rainfall
74
mm
Sun Hours
10.7
Hrs
