Ottawa Weather in September
Canada · September climate averages and travel tips
Avg high22°C (71°F)
Avg low10°C (50°F)
Rainfall81 mm (3.2 in)
RatingExcellent 8.7/10
Expect warm days in Ottawa in September: the average high is 22°C (71°F) and the average low is 10°C (50°F). September is autumn (fall) in Canada. The month is moderately rainy, with about 81 mm (3.2 in) of rain spread over 12 days. You get roughly 12.3 hours of daylight and a mix of sun and cloud.
Is September a good time to visit Ottawa?
Yes — September is one of the best months to visit Ottawa. The weather rates excellent (8.7/10) on our comfort score.
September weather at a glance
| Average high | 22°C (71°F) |
|---|---|
| Average low | 10°C (50°F) |
| Daily mean | 16°C (60°F) |
| Rainfall | 81 mm (3.2 in) |
| Rainy days (1 mm+) | 12 |
| Humidity | 78% |
| Cloud cover | 54% |
| Daylight | 12.3 hours |
| Est. sunshine | 6.2 hours/day |
| Wind | 1.1 km/h |
| vs August | 4°C cooler than August, with 13 mm less rain. |
What to pack for Ottawa in September
- T-shirts plus a light layer for the evening
- a sweater for cool nights
- an umbrella or rain jacket
Ottawa weather in other months
Jan-6°C / -16°C64 mmPoorFeb-5°C / -15°C55 mmPoorMar2°C / -9°C61 mmPoorApr11°C / 0°C89 mmFairMay19°C / 7°C78 mmExcellentJun23°C / 12°C102 mmGoodJul26°C / 15°C103 mmFairAug25°C / 15°C94 mmGoodSep22°C / 10°C81 mmExcellentOct14°C / 4°C93 mmFairNov5°C / -3°C65 mmPoorDec-3°C / -11°C81 mmPoor
← AugustBest time to visit OttawaOctober →
Better weather in September nearby
- San Francisco, California24°C · 4 mm · Excellent
- Seattle, Washington21°C · 62 mm · Excellent
- Denver, Colorado29°C · 35 mm · Excellent
Nearby in September
- Montreal21°C · 82 mm
- Toronto22°C · 62 mm
- Quebec19°C · 107 mm
- Boston, Massachusetts24°C · 97 mm
- The Bronx, New York25°C · 104 mm
- Manhattan, New York25°C · 104 mm
Where else is good in September? See where to go in September.