Ottawa
August
Weather in Ottawa for August 2025
Your guide to Ottawa weather in August - trends and predictions
In general, the average temperature in Ottawa at the beginning of August is 24.7 °C. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 22.6 °C by the end of August.
Ottawa experiences an exceptionally high level of rainfall in August, with more than 20 rainy days on average.
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10
Dry days
21
Rainy days
0
Snow days
23°/13°
Temperatures
15 km/h
Avg max wind
77 %
Avg humidity
Ottawa in August average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  25° | 2  27° | 3  26° | ||||
| 4 27° | 5 23° | 6 24° | 7 21° | 8 21° | 9 24° | 10 22° |
| 11 21° | 12 22° | 13 24° | 14 25° | 15 25° | 16 27° | 17 24° |
| 18 22° | 19 19° | 20  21° | 21 21° | 22 21° | 23 24° | 24 23° |
| 25  23° | 26 23° | 27 25° | 28 22° | 29 23° | 30  20° | 31  22° |
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Temperatures trend during August in Ottawa
See the weather trend as well as the moving average line
August weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Aug. | Patchy rain possible | 25° /14° | 0.6 mm | 6 | |
| 2 Aug. | Overcast | 27° /15° | 0 mm | 7 | |
| 3 Aug. | Moderate or heavy rain shower | 26° /17° | 19 mm | 6 | |
| 4 Aug. | Patchy rain possible | 27° /16° | 2.1 mm | 6 | |
| 5 Aug. | Overcast | 23° /13° | 3.3 mm | 5 | |
| 6 Aug. | Overcast | 24° /12° | 0 mm | 6 | |
| 7 Aug. | Moderate or heavy rain shower | 21° /13° | 7.9 mm | 5 | |
| 8 Aug. | Moderate or heavy rain shower | 21° /13° | 21.6 mm | 5 | |
| 9 Aug. | Patchy rain possible | 24° /16° | 10.3 mm | 6 | |
| 10 Aug. | Moderate or heavy rain shower | 22° /13° | 12 mm | 5 | |
| 11 Aug. | Patchy rain possible | 21° /12° | 4.2 mm | 5 | |
| 12 Aug. | Moderate or heavy rain shower | 22° /12° | 11.7 mm | 5 | |
| 13 Aug. | Patchy rain possible | 24° /13° | 0.8 mm | 5 | |
| 14 Aug. | Patchy rain possible | 25° /14° | 1 mm | 6 | |
| 15 Aug. | Patchy rain possible | 25° /15° | 0.3 mm | 6 | |
| 16 Aug. | Patchy rain possible | 27° /16° | 0.5 mm | 6 | |
| 17 Aug. | Patchy rain possible | 24° /17° | 7.6 mm | 6 | |
| 18 Aug. | Moderate or heavy rain shower | 22° /16° | 18.3 mm | 5 | |
| 19 Aug. | Overcast | 19° /12° | 1.6 mm | 4 | |
| 20 Aug. | Cloudy | 21° /11° | 0.3 mm | 5 | |
| 21 Aug. | Patchy rain possible | 21° /11° | 0.9 mm | 5 | |
| 22 Aug. | Patchy rain possible | 21° /11° | 0.4 mm | 5 | |
| 23 Aug. | Patchy rain possible | 24° /13° | 0.1 mm | 6 | |
| 24 Aug. | Patchy rain possible | 23° /13° | 1.4 mm | 5 | |
| 25 Aug. | Fog | 23° /14° | 2.4 mm | 6 | |
| 26 Aug. | Light rain shower | 23° /15° | 6.5 mm | 6 | |
| 27 Aug. | Cloudy | 25° /12° | 0.2 mm | 6 | |
| 28 Aug. | Mist | 22° /12° | 1.6 mm | 5 | |
| 29 Aug. | Patchy rain possible | 23° /9° | 0.9 mm | 6 | |
| 30 Aug. | Moderate or heavy rain with thunder | 20° /10° | 0.8 mm | 5 | |
| 31 Aug. | Partly cloudy | 22° /11° | 2 mm | 6 | |
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Important Notice
Our weather forecast for Ottawa in August 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.
Ottawa in August - FAQ
What are the expected maximum and minimum temperatures in Ottawa during August?
Enjoy moderate daytime temperatures of up to 23° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Ottawa during August?
Significant rainfall exceeding 193.9 mm is expected in Ottawa during August, occurring over more than 21 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Ottawa during August?
The average wind speed in Ottawa during August is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
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