The highest day temperature in August 2025 was 100°F. The lowest night temperature was 52°F. The average values for day and night temperatures during August were 82.5°F и 63.4°F respectivly.

Most of the days in August are sunny but you can also expect cloudy and gloomy days.

Precipitation total in August for Ottawa is 2.8 in. It makes august one of the most rainy months of the year.

The average wind speed in August is 7.0 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Ottawa in August is 8.8 hours.