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Canada weather

Weather in Ottawa for September 2027

Your guide to Ottawa weather in September - trends and predictions

    Temperatures

  • In general, the average temperature in Ottawa at the beginning of September is 24.1 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.2 °C by the end of September.

    • Rain 🌧️

  • With an average of 5 rainy days, Ottawa experiences minimal rainfall in September.

    • More

  • Is September a good time to visit Ottawa? check out the best time to travel to Ottawa page.

  • ✨ Is September a good time to visit Ottawa? – Ask the AI Weatherman

Average dry days
25
Dry days
Average rainy days
5
Rainy days
Average snowy days
0
Snow days
Average temperatures
22°/11°
Temperatures
Average wind speed
14 km/h
Avg max wind
Average humidity
72 %
Avg humidity

Ottawa Weather September

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

Temperatures trend during September in Ottawa

See the weather trend as well as the moving average line

September weather in Ottawa day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
1 Sept. Heavy rain
Heavy rain
 24° /13° 55.9 mm 5
2 Sept. Light rain
Light rain
 24° /14° 3.3 mm 5
3 Sept. Moderate rain
Moderate rain
 26° /14° 12.7 mm 6.9
4 Sept. Patchy rain possible
Patchy rain possible
 26° /15° 1.4 mm 6.8
5 Sept. Mist
Mist
 25° /13° 0.1 mm 6
6 Sept. Overcast
Overcast
 24° /14° 0.1 mm 6
7 Sept. Thundery outbreaks possible
Thundery outbreaks possible
 22° /12° 4.1 mm 5
8 Sept. Moderate rain
Moderate rain
 18° /12° 12.7 mm 4
9 Sept. Light rain
Light rain
 22° /9° 4.6 mm 4
10 Sept. Overcast
Overcast
 22° /10° 0 mm 6
11 Sept. Overcast
Overcast
 22° /11° 0 mm 5
12 Sept. Overcast
Overcast
 23° /12° 0 mm 5
13 Sept. Mist
Mist
 21° /14° 0.4 mm 4
14 Sept. Mist
Mist
 20° /12° 0 mm 5
15 Sept. Partly cloudy
Partly cloudy
 22° /11° 0.2 mm 5
16 Sept. Overcast
Overcast
 24° /13° 0 mm 5
17 Sept. Patchy rain possible
Patchy rain possible
 25° /12° 0.3 mm 5
18 Sept. Patchy light drizzle
Patchy light drizzle
 22° /12° 0.4 mm 5
19 Sept. Overcast
Overcast
 20° /10° 0 mm 5
20 Sept. Overcast
Overcast
 20° /9° 0 mm 5
21 Sept. Overcast
Overcast
 20° /7° 0 mm 4
22 Sept. Overcast
Overcast
 19° /9° 0 mm 5
23 Sept. Patchy rain possible
Patchy rain possible
 20° /11° 1.9 mm 5
24 Sept. Overcast
Overcast
 21° /11° 0 mm 5
25 Sept. Heavy rain
Heavy rain
 18° /10° 45.6 mm 4
26 Sept. Patchy rain possible
Patchy rain possible
 21° /11° 1.1 mm 4
27 Sept. Mist
Mist
 20° /10° 0.3 mm 4
28 Sept. Partly cloudy
Partly cloudy
 20° /11° 0 mm 4
29 Sept. Mist
Mist
 22° /10° 0 mm 4.5
30 Sept. Partly cloudy
Partly cloudy
 20° /11° 0 mm 4
Next
Important Notice
Our weather forecast for Ottawa 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 Ottawa forecast closer to your planned date for the most up-to-date weather information.
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Ottawa in September - FAQ

What are the expected maximum and minimum temperatures in Ottawa during September?
Enjoy moderate daytime temperatures of up to 22° and cooler nights around 11°. Ideal for a range of outdoor activities, from hiking to city tours.

How much rainfall should be expected in Ottawa during September?
Significant rainfall exceeding 145 mm is expected in Ottawa during September, occurring over more than 5 days. Preparing for wet conditions is recommended in your planning.

What are the typical wind conditions in Ottawa during September?
The average wind speed in Ottawa during September is 14 km/h, suggesting breezy to windy conditions, depending on your activities.

September rainfall patterns in Ottawa

Explore the daily rainfall trends and prepare for Ottawas September weather 💧
Typically, Ottawa has 5 rainy days in September with a total of 145 mm of rainfall.

UV exposure in Ottawa during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Location coordinates Where is Ottawa?

Get accurate weather forecasts for Ottawa, located at latitude 45.411 and longitude -75.698. Stay updated with localized weather information tailored for Ottawa.

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