St. Catharines
September
Weather in St. Catharines for September 2025
Your guide to St. Catharines weather in September - trends and predictions
In general, the average temperature in St. Catharines at the beginning of September is 25.3 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.9 °C by the end of September.
St. Catharines sees moderate rainfall in September, averaging 7 rainy days.
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23
Dry days
7
Rainy days
0
Snow days
23°/14°
Temperatures
21 km/h
Avg max wind
72 %
Avg humidity
St. Catharines in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  23° | 2 22° | 3  25° | 4  27° | 5 29° | 6 29° | 7  22° |
| 8 21° | 9  21° | 10 20° | 11 23° | 12 24° | 13 20° | 14 22° |
| 15 23° | 16 23° | 17 21° | 18 21° | 19 22° | 20  22° | 21 25° |
| 22 24° | 23 21° | 24 21° | 25 23° | 26 23° | 27 19° | 28 19° |
| 29 21° | 30 20° |
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Temperatures trend during September in St. Catharines
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. | Mist | 23° /15° | 0.4 mm | 5 | |
| 2 Sept. | Mist | 22° /14° | 0.2 mm | 6 | |
| 3 Sept. | Thundery outbreaks possible | 25° /16° | 0 mm | 6 | |
| 4 Sept. | Partly cloudy | 27° /17° | 0 mm | 7 | |
| 5 Sept. | Partly cloudy | 29° /18° | 0 mm | 8 | |
| 6 Sept. | Thundery outbreaks possible | 29° /18° | 0.7 mm | 7 | |
| 7 Sept. | Light rain shower | 22° /15° | 4.8 mm | 5 | |
| 8 Sept. | Mist | 21° /13° | 0.1 mm | 5 | |
| 9 Sept. | Overcast | 21° /15° | 0.4 mm | 5 | |
| 10 Sept. | Light rain shower | 20° /16° | 0.5 mm | 5 | |
| 11 Sept. | Overcast | 23° /15° | 0 mm | 5 | |
| 12 Sept. | Mist | 24° /16° | 0.6 mm | 6 | |
| 13 Sept. | Overcast | 20° /14° | 0 mm | 5 | |
| 14 Sept. | Partly cloudy | 22° /14° | 0 mm | 6 | |
| 15 Sept. | Partly cloudy | 23° /14° | 0 mm | 6 | |
| 16 Sept. | Mist | 23° /14° | 0 mm | 6 | |
| 17 Sept. | Mist | 21° /14° | 0.1 mm | 5 | |
| 18 Sept. | Patchy rain possible | 21° /15° | 0.3 mm | 5 | |
| 19 Sept. | Overcast | 22° /13° | 0 mm | 5 | |
| 20 Sept. | Sunny | 22° /13° | 0 mm | 6 | |
| 21 Sept. | Mist | 25° /14° | 1.6 mm | 6 | |
| 22 Sept. | Partly cloudy | 24° /13° | 0 mm | 6 | |
| 23 Sept. | Overcast | 21° /14° | 6.5 mm | 5 | |
| 24 Sept. | Overcast | 21° /13° | 0 mm | 5 | |
| 25 Sept. | Partly cloudy | 23° /16° | 4.2 mm | 6 | |
| 26 Sept. | Mist | 23° /14° | 0 mm | 5 | |
| 27 Sept. | Overcast | 19° /13° | 0 mm | 5 | |
| 28 Sept. | Patchy rain possible | 19° /13° | 1.9 mm | 5 | |
| 29 Sept. | Overcast | 21° /16° | 0 mm | 5 | |
| 30 Sept. | Mist | 20° /14° | 0 mm | 5 | |
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Important Notice
Our weather forecast for St. Catharines 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 St. Catharines forecast closer to your planned date for the most up-to-date weather information.
St. Catharines in September - FAQ
What are the expected maximum and minimum temperatures in St. Catharines 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 St. Catharines during September?
Expect minimal rainfall in St. Catharines during September, with a total of 10.8 mm over approximately 7 days. This minimal precipitation is unlikely to significantly impact plans.
What are the typical wind conditions in St. Catharines during September?
The average wind speed in St. Catharines during September is 21 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in St. Catharines
Explore the daily rainfall trends and prepare for St. Cathariness September weather 💧
UV exposure in St. Catharines during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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