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.
With an average of 5 rainy days, St. Catharines experiences minimal rainfall in September.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
25
Dry days
5
Rainy days
0
Snow days
22°/15°
Temperatures
20 km/h
Avg max wind
74 %
Avg humidity
St. Catharines in September average weather
Move between months or click on a day
| 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° |
You can click on date
Access St. Catharines weather forecasts with a simple click. Select any date for comprehensive insights on temperature, rainfall, and wind conditions.
Temperatures trend during September in St. Catharines
See the weather trend as well as the moving average line
September weather day by day
Click on a date for more information
| 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 | |
| Next | |||||
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?
During September, expect a variety of temperatures with highs around 22° and lows near 15°, suitable for diverse activities and preferences.
How much rainfall should be expected in St. Catharines during September?
In September, St. Catharines can expect light to moderate rainfall, totaling 22.4 mm across approximately 5 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in St. Catharines during September?
The average wind speed in St. Catharines during September is 20 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 ☀️
Quick links
You are here
Where is St. Catharines?Get accurate weather forecasts for St. Catharines, located at latitude 43.171 and longitude -79.243. Stay updated with localized weather information tailored for St. Catharines.
Found a mistake?
We appreciate your attention to details. Tell us here.