Ontario
September
Weather in Ontario for September 2025
Your guide to Ontario weather in September - trends and predictions
In general, the average temperature in Ontario at the beginning of September is 33 °F. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 30.1 °F by the end of September.
With an average of 4 rainy days, Ontario experiences minimal rainfall in September, ensuring that most days remain pleasantly dry.
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26
Dry days
4
Rainy days
0
Snow days
28°/15°
Temperatures
15 km/h
Avg max wind
55 %
Avg humidity
Ontario in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  32° | 2  32° | 3 30° | 4  32° | 5 34° | 6 35° | 7  36° |
| 8 36° | 9 37° | 10  34° | 11 31° | 12 29° | 13 27° | 14 28° |
| 15 28° | 16 25° | 17 24° | 18  23° | 19 22° | 20 22° | 21 22° |
| 22 28° | 23 31° | 24 31° | 25 30° | 26 31° | 27 32° | 28 30° |
| 29 30° | 30 27° |
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Temperatures trend during September in Ontario
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Patchy rain possible | 32° /18° | 2.3 mm | 7 | |
| Sept. 2 | Light rain | 32° /18° | 1.1 mm | 8 | |
| Sept. 3 | Light rain | 30° /16° | 3.5 mm | 8 | |
| Sept. 4 | Partly cloudy | 32° /17° | 0 mm | 8 | |
| Sept. 5 | Partly cloudy | 34° /19° | 0 mm | 8 | |
| Sept. 6 | Partly cloudy | 35° /20° | 0 mm | 9 | |
| Sept. 7 | Sunny | 36° /21° | 0 mm | 9 | |
| Sept. 8 | Partly cloudy | 36° /22° | 0 mm | 8 | |
| Sept. 9 | Sunny | 37° /23° | 0 mm | 9 | |
| Sept. 10 | Overcast | 34° /21° | 0 mm | 8 | |
| Sept. 11 | Partly cloudy | 31° /18° | 0 mm | 8 | |
| Sept. 12 | Sunny | 29° /15° | 0 mm | 8 | |
| Sept. 13 | Sunny | 27° /15° | 0 mm | 7 | |
| Sept. 14 | Partly cloudy | 28° /14° | 0 mm | 7 | |
| Sept. 15 | Partly cloudy | 28° /16° | 0 mm | 7 | |
| Sept. 16 | Partly cloudy | 25° /13° | 0.1 mm | 7 | |
| Sept. 17 | Partly cloudy | 24° /13° | 0 mm | 6 | |
| Sept. 18 | Cloudy | 23° /12° | 0 mm | 6 | |
| Sept. 19 | Partly cloudy | 22° /12° | 0 mm | 6 | |
| Sept. 20 | Partly cloudy | 22° /11° | 0 mm | 6 | |
| Sept. 21 | Patchy rain possible | 22° /11° | 0.1 mm | 6 | |
| Sept. 22 | Overcast | 28° /13° | 0 mm | 7 | |
| Sept. 23 | Partly cloudy | 31° /18° | 0 mm | 8 | |
| Sept. 24 | Partly cloudy | 31° /18° | 0 mm | 8 | |
| Sept. 25 | Sunny | 30° /16° | 0 mm | 8 | |
| Sept. 26 | Overcast | 31° /15° | 0 mm | 7 | |
| Sept. 27 | Partly cloudy | 32° /16° | 0 mm | 8 | |
| Sept. 28 | Sunny | 30° /17° | 0 mm | 8 | |
| Sept. 29 | Sunny | 30° /16° | 0 mm | 8 | |
| Sept. 30 | Light rain shower | 27° /15° | 1.7 mm | 7 | |
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Important Notice
Our weather forecast for Ontario in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Ontario forecast closer to your planned date for the most up-to-date weather information.
Ontario in September - FAQ
What are the expected maximum and minimum temperatures in Ontario during September?
During September, expect a variety of temperatures with highs around 28° and lows near 15°, suitable for diverse activities and preferences.
How much rainfall should be expected in Ontario during September?
Expect minimal rainfall in Ontario during September, with a total of 17.4 mm over approximately 4 days. This minimal precipitation is unlikely to significantly impact plans.
What are the typical wind conditions in Ontario during September?
The average wind speed in Ontario during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
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