Sarnia
September
Weather in Sarnia for September 2025
Your guide to Sarnia weather in September - trends and predictions
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 21.1 °C by the end of September.
Sarnia experiences moderate rainfall in September, with an average of 6 rainy days and a total precipitation of 40.5 mm.
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Temperatures
Rain 🌧️
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24
Dry days
6
Rainy days
0
Snow days
23°/14°
Temperatures
19 km/h
Avg max wind
74 %
Avg humidity
Sarnia in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  23° | 2  22° | 3  28° | 4  29° | 5  30° | 6  26° | 7 20° |
| 8 20° | 9 22° | 10 23° | 11 25° | 12  24° | 13 22° | 14 23° |
| 15 25° | 16 25° | 17 23° | 18 20° | 19 20° | 20 24° | 21 25° |
| 22 25° | 23 20° | 24 21° | 25 22° | 26 23° | 27 20° | 28 19° |
| 29 21° | 30 22° |
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Temperatures trend during September in Sarnia
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 |
|---|---|---|---|---|---|
| 1 Sept. | Sunny | 23° /13° | 0 mm | 6 | |
| 2 Sept. | Overcast | 22° /12° | 0 mm | 6 | |
| 3 Sept. | Cloudy | 28° /14° | 0 mm | 7 | |
| 4 Sept. | Partly cloudy | 29° /15° | 0 mm | 8 | |
| 5 Sept. | Mist | 30° /17° | 0 mm | 7 | |
| 6 Sept. | Patchy rain possible | 26° /16° | 6.9 mm | 6 | |
| 7 Sept. | Light rain shower | 20° /13° | 4.4 mm | 5 | |
| 8 Sept. | Patchy rain possible | 20° /10° | 0.1 mm | 5 | |
| 9 Sept. | Cloudy | 22° /13° | 0 mm | 6 | |
| 10 Sept. | Overcast | 23° /14° | 0 mm | 6 | |
| 11 Sept. | Fog | 25° /14° | 0.4 mm | 6 | |
| 12 Sept. | Torrential rain shower | 24° /15° | 13.7 mm | 6 | |
| 13 Sept. | Overcast | 22° /13° | 0 mm | 6 | |
| 14 Sept. | Partly cloudy | 23° /14° | 0 mm | 6 | |
| 15 Sept. | Mist | 25° /13° | 0 mm | 6 | |
| 16 Sept. | Mist | 25° /12° | 0 mm | 6 | |
| 17 Sept. | Patchy rain possible | 23° /13° | 0.4 mm | 5 | |
| 18 Sept. | Light rain shower | 20° /13° | 0.6 mm | 5 | |
| 19 Sept. | Fog | 20° /11° | 0 mm | 5 | |
| 20 Sept. | Patchy rain possible | 24° /13° | 0 mm | 5 | |
| 21 Sept. | Mist | 25° /16° | 0 mm | 6 | |
| 22 Sept. | Fog | 25° /15° | 2.6 mm | 6 | |
| 23 Sept. | Fog | 20° /13° | 9.5 mm | 5 | |
| 24 Sept. | Overcast | 21° /14° | 0 mm | 5 | |
| 25 Sept. | Partly cloudy | 22° /14° | 0 mm | 6 | |
| 26 Sept. | Patchy rain possible | 23° /14° | 0.3 mm | 6 | |
| 27 Sept. | Overcast | 20° /13° | 0 mm | 5 | |
| 28 Sept. | Light rain shower | 19° /15° | 1.4 mm | 4 | |
| 29 Sept. | Patchy rain possible | 21° /15° | 0.2 mm | 5 | |
| 30 Sept. | Overcast | 22° /15° | 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.
Sarnia in September - FAQ
What are the expected maximum and minimum temperatures in Sarnia during September?
Enjoy moderate daytime temperatures of up to 23° and cooler nights around 14°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Sarnia during September?
In September, Sarnia can expect light to moderate rainfall, totaling 40.5 mm across approximately 6 days. Occasional showers are possible, and planning ahead for them could be helpful.
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 💧
UV exposure in Sarnia during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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