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Weather in St. Catharines for September 2026

Your guide to St. Catharines weather in September - trends and predictions

    Temperatures

  • So far, September 2026 in St. Catharines is slightly warmer than the historical average by 2 °C.

  • Expect cooler weather in the next days in St. Catharines with the forecast suggesting a temperature of 20.3 °C, lower than the historical average.

  • In general, the average temperature in St. Catharines at the beginning of September is 25.1 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.3 °C by the end of September.

    • Rain 🌧️

  • St. Catharines experiences moderate rainfall in September, with an average of 7 rainy days and a total precipitation of 29.3 mm.

    • More

  • New! Chat with our AI weatherman - it’s amazing and free.

Average dry days
23
Dry days
Average rainy days
7
Rainy days
Average snowy days
0
Snow days
Average temperatures
22°/14°
Temperatures
Average wind speed
20 km/h
Avg max wind
Average humidity
75 %
Avg humidity

St. Catharines Weather September

Move between months or click on a day
August
October
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
1
Mist
25°
2
Mist
25°
3
Thundery outbreaks possible
26°
4
Sunny
25°
5
Partly cloudy
27°
6
Overcast
26°
7
Light rain shower
22°
8
Mist
22°
9
Overcast
24°
10
Overcast
22°
11
Overcast
23°
12
Sunny
28°
13
Patchy rain possible
23°
14
Sunny
17°
15
Overcast
22°
16
Overcast
22°
17
Patchy rain possible
20°
18
Patchy rain possible
22°
19
Light rain shower
20°
20
Sunny
16°
21
Sunny
17°
22
Overcast
19°
23
Patchy rain possible
21°
24
Patchy rain possible
18°
25
Sunny
19°
26
Mist
22°
27
Fog
21°
28
Patchy rain possible
20°
29
Overcast
21°
30
Mist
21°

Temperatures trend during September in St. Catharines

See the weather trend as well as the moving average line

September weather in St. Catharines day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
1 Sept. Mist
Mist
 25° /15° 0.3 mm 6
2 Sept. Mist
Mist
 25° /16° 9.5 mm 5
3 Sept. Thundery outbreaks possible
Thundery outbreaks possible
 26° /15° 0 mm 6
4 Sept. Sunny
Sunny
 25° /16° 3.7 mm 7
5 Sept. Partly cloudy
Partly cloudy
 27° /15° 0 mm 7
6 Sept. Overcast
Overcast
 26° /16° 0.4 mm 6
7 Sept. Light rain shower
Light rain shower
 22° /13° 2.4 mm 5
8 Sept. Mist
Mist
 22° /13° 0 mm 4
9 Sept. Overcast
Overcast
 24° /15° 4.3 mm 5
10 Sept. Overcast
Overcast
 22° /16° 0.3 mm 5
11 Sept. Overcast
Overcast
 23° /14° 0 mm 6
12 Sept. Sunny
Sunny
 28° /13° 0 mm 5.9
13 Sept. Patchy rain possible
Patchy rain possible
 23° /18° 0.8 mm 5.7
14 Sept. Sunny
Sunny
 17° /14° 0 mm 5.7
15 Sept. Overcast
Overcast
 22° /13° 0.7 mm 5
16 Sept. Overcast
Overcast
 22° /20° 0 mm 6
17 Sept. Patchy rain possible
Patchy rain possible
 20° /16° 2.2 mm 5
18 Sept. Patchy rain possible
Patchy rain possible
 22° /16° 18.5 mm 5
19 Sept. Light rain shower
Light rain shower
 20° /14° 22.4 mm 4
20 Sept. Sunny
Sunny
 16° /14° 0 mm 5
21 Sept. Sunny
Sunny
 17° /13° 0 mm 5
22 Sept. Overcast
Overcast
 19° /14° 0 mm 4
23 Sept. Patchy rain possible
Patchy rain possible
 21° /17° 0.1 mm 6
24 Sept. Patchy rain possible
Patchy rain possible
 18° /12° 0.4 mm 4
25 Sept. Sunny
Sunny
 19° /10° 0.6 mm 5
26 Sept. Mist
Mist
 22° /14° 0 mm 5
27 Sept. Fog
Fog
 21° /14° 0 mm 5
28 Sept. Patchy rain possible
Patchy rain possible
 20° /13° 1.2 mm 5
29 Sept. Overcast
Overcast
 21° /13° 0 mm 5
30 Sept. Mist
Mist
 21° /13° 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.
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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 22° 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?
In September, St. Catharines can expect light to moderate rainfall, totaling 29.3 mm across approximately 7 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 💧
Typically, St. Catharines has 7 rainy days in September with a total of 29.3 mm of rainfall.

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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Location coordinates 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.

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