Ottawa · August
Run in the morning.
Comfortable average high of 77°F, dipping to 62°F at night. Humidity averages 76% — the limiting factor on most runs. Expect 17 rain days — plan around the radar. Humidity rises with the sun — morning runs catch the driest, coolest window.
Avg high / low
77° / 62°F
Humidity
76%
Rain days
17/mo
Wind
9 mph
What August feels like in Ottawa
Sunrise
06:05
Mid-month average
Sunset
20:08
Mid-month average
Time-of-day breakdown
Morning
Coolest, driest air of the day. The window before sunrise is the most reliable comfortable hour.
Midday
Mild but UV and traffic peak. Workable if you don't mind shifting your pace.
Evening
Warm and runnable. Crowded routes but the air's typically calm.
What to wear running in Ottawa in August
The kit for August in Ottawa: shorts and a short-sleeve are the standard kit, a water-resistant cap or jacket on standby.
August vs the surrounding months
vs July
-2° avg high
+1 rain days
Ottawa in July →
August
77°F avg high
17 rain days
Best: morning
vs September
+6° avg high
+4 rain days
Ottawa in September →
Frequently Asked Questions
What is the best time of day to run in Ottawa in August?+
Morning. Humidity rises with the sun — morning runs catch the driest, coolest window.
What's the average temperature in Ottawa in August?+
Average high 77°F, average low 62°F.
How does August compare to surrounding months in Ottawa?+
Compared to July (avg high 79°F), August is cooler. Compared to September (avg high 71°F), August is warmer.
Does it rain often in Ottawa in August?+
Expect about 17 measurable rain days in August, on average.