The temperatures in Ottawa in August are comfortable with low of 15°C and and high up to 25°C.
You can expect about 3 to 8 days of rain in Ottawa during the month of August. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Ottawa in August 2025.
If you’re planning to visit Ottawa in the near future, we highly recommend that you review the 14 day weather forecast for Ottawa before you arrive.
Temperatures
25° / 15°
Rainy Days
7
Snowy Days
0
Dry Days
24
Rainfall
137
mm
Sun Hours
10.7
Hrs
