Sarnia
September
Weather in Sarnia for September 2026
Your guide to Sarnia weather in September - trends and predictions
So far, September 2026 in Sarnia shows a warmer trend than usual by 3.2 °C.
Expect cooler weather in the next days in Sarnia with the forecast suggesting a temperature of 20.4 °C, lower than the historical average.
In general, the average temperature in Sarnia at the beginning of September is 25.4 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.9 °C by the end of September.
Sarnia experiences moderate rainfall in September, with an average of 9 rainy days and a total precipitation of 75 mm.
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Temperatures
Rain 🌧️
More
21
Dry days
9
Rainy days
0
Snow days
22°/13°
Temperatures
19 km/h
Avg max wind
76 %
Avg humidity
Sarnia Weather September
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Temperatures trend during September in Sarnia
See the weather trend as well as the moving average line
September weather in Sarnia day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Sunny | 26° /14° | 0 mm | 6 | |
| 2 Sept. |  Overcast | 26° /13° | 3.8 mm | 5 | |
| 3 Sept. | Sunny | 28° /14° | 1.8 mm | 6 | |
| 4 Sept. |  Partly cloudy | 26° /14° | 12.6 mm | 6 | |
| 5 Sept. | Sunny | 27° /14° | 0 mm | 7 | |
| 6 Sept. |  Patchy rain possible | 24° /13° | 3.4 mm | 6 | |
| 7 Sept. | Light rain shower | 21° /12° | 2.2 mm | 5 | |
| 8 Sept. | Patchy rain possible | 22° /10° | 0 mm | 4 | |
| 9 Sept. | Partly cloudy | 24° /13° | 3.3 mm | 5 | |
| 10 Sept. | Overcast | 24° /14° | 0.1 mm | 5 | |
| 11 Sept. | Partly cloudy | 24° /13° | 0.2 mm | 6 | |
| 12 Sept. | Sunny | 26° /15° | 0.6 mm | 4.9 | |
| 13 Sept. | Sunny | 21° /14° | 0.1 mm | 5.8 | |
| 14 Sept. | Sunny | 17° /12° | 0.1 mm | 4.7 | |
| 15 Sept. | Overcast | 21° /15° | 5.7 mm | 5 | |
| 16 Sept. | Overcast | 22° /18° | 3 mm | 6 | |
| 17 Sept. | Light rain shower | 24° /17° | 12.5 mm | 5 | |
| 18 Sept. | Sunny | 18° /15° | 0 mm | 5 | |
| 19 Sept. | Sunny | 18° /15° | 0 mm | 5 | |
| 20 Sept. | Sunny | 19° /14° | 0 mm | 5 | |
| 21 Sept. | Sunny | 20° /15° | 0 mm | 5 | |
| 22 Sept. | Sunny | 21° /13° | 0 mm | 6 | |
| 23 Sept. | Sunny | 18° /11° | 0 mm | 5 | |
| 24 Sept. | Overcast | 18° /11° | 0 mm | 4 | |
| 25 Sept. | Sunny | 22° /13° | 0 mm | 6 | |
| 26 Sept. | Patchy rain possible | 21° /14° | 0.2 mm | 5 | |
| 27 Sept. | Overcast | 22° /14° | 0 mm | 5 | |
| 28 Sept. | Overcast | 20° /14° | 0.9 mm | 4 | |
| 29 Sept. |  Mist | 21° /14° | 0.1 mm | 5 | |
| 30 Sept. | Overcast | 22° /13° | 0 mm | 5 | |
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Important Notice
Our weather forecast for Sarnia 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 Sarnia forecast closer to your planned date for the most up-to-date weather information.
Change Month
Sarnia in September - FAQ
What are the expected maximum and minimum temperatures in Sarnia during September?
Enjoy moderate daytime temperatures of up to 22° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Sarnia during September?
Moderate rainfall is anticipated in Sarnia during September, with a total of 75 mm spread over approximately 9 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Sarnia during September?
The average wind speed in Sarnia during September is 19 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Sarnia
Explore the daily rainfall trends and prepare for Sarnias September weather 💧
Typically, Sarnia has 9 rainy days in September with a total of 75 mm of rainfall.
UV exposure in Sarnia during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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