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Climate · Ottawa

Ottawa in August

Warm and damp, as the days shorten.

Typical weather, averaged over 30 years

August in Ottawa is warm: highs near 80°F, lows near 62°F. Rain falls on about three days a week, and the days shorten by 1 hour 22 minutes from the first week to the last.August in Ottawa is warm: highs near 27°C, lows near 17°C. Rain falls on about three days a week, and the days shorten by 1 hour 22 minutes from the first week to the last.

High
80°F27°Caverage
Low
62°F17°Caverage
Wet days
3a week · 36% of days
Daylight
14h 02mon average

Is August a good time to visit Ottawa?

Yes. August is one of Ottawa's best months (June, or August to September).

How we judge it: every month is scored on how close its typical high comes to the range from 70°F to 80°F, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.How we judge it: every month is scored on how close its typical high comes to the range from 21°C to 27°C, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.

How August sits in the year

week by week

Temperature

Highs near 80°F in August, against 28°F to 82°F through the year.Highs near 27°C in August, against -2°C to 28°C through the year.

Chance of a wet day

36% of days in August, against 32% to 43% through the year.

Cloud cover

42% cover in August, against 42% to 70% through the year.

Daylight

14h 02m in August, against 8h 46m to 15h 36m through the year.

Week by week, lightly smoothed, with August shaded. The olive line marks the best months. Hover or tap a week for its figures.

Either side

  1. July82°28°low 62°low 17°3 wet days a weekRain on about three days a week.
  2. August80°27°low 62°low 17°3 wet days a weekRain on about three days a week.
  3. September74°23°low 55°low 13°2 wet days a weekRain on about two days a week.

Where Ottawa sits, in August

America/Toronto
this place
typical high in August 40°F4°C95°F35°C
Sunrise, mid-August
6:03 AMsets 8:13 PM
Above the sea
70 mlow-lying
Latitude
45.4°Nnorthern hemisphere
Nearest of ours
Mont-Tremblant115 km north-east

The land around Ottawa, shaded by its typical high in August, the planning map's own layer. Hover the map for the figure at that spot; tap it on a phone. Clock times are local, for the 15th.

Elsewhere in Canada in August

high · low · wet days
See August on the planning mapThe whole year in Ottawa

Typical weather, averaged over 30 years (1995–2024), from the 11 km grid square nearest Ottawa. Temperatures are adjusted against 66 weather stations: daytime highs read about 3.1°F cold in the source data and are raised to match.Temperatures are adjusted against 66 weather stations: daytime highs read about 1.7°C cold in the source data and are raised to match. Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not. Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.

Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not.

Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.