Ottawa Weather in September
20.8°C high · 10°C low · 86 mm rain · 6h sun
Sep is a warm month in Ottawa — not peak season, but a good time to avoid crowds.
September at a glance
| Metric | Value |
|---|---|
| Average high | 20.8°C |
| Average low | 10°C |
| Rainfall | 86 mm |
| Sunshine | 6 hours/day |
| Daylight | 12.3 hours |
What to pack in September
Pack a jacket and layers for Ottawa in September.
Ottawa weather by month
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Frequently asked questions
What is the weather in Ottawa in September?
Highs of 20.8°C and lows of 10°C, with about 86 mm of rain and 6 hours of sunshine per day.
Is September a good time to visit Ottawa?
Sep is a warm month in Ottawa — not peak season, but a good time to avoid crowds.
What to do in Ottawa · Best time to visit Ottawa
Climate data: Open-Meteo Historical (ERA5), 1991–2020. CC BY 4.0.