Ottawa in September
8.0out of 10
Yes, a good time to go
Warm and comfortable: highs around 25°C. Some rain: about 8 rainy days.
25°CAvg high
14°CAvg low
8Rainy days (79 mm)
12:16 hDaylight
06:42Sunrise · 18:57 Sunset
Why this score
- Warm and comfortable: highs around 25°C
- Some rain: about 8 rainy days
What to wear and pack
- T-shirts and light layers
- A light jacket for cooler evenings
- Rain jacket or compact umbrella
How reliable is the forecast?
Rainfall in September is fairly consistent from year to year (2.9 days). Averages cover 30 years (1991–2020). Individual days can differ a lot.
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | 0°C | -8°C | 55 mm | 8 | – | – | 4.0 |
| February | 3°C | -5°C | 51 mm | 7 | – | – | 4.6 |
| March | 10°C | 0°C | 72 mm | 10 | – | – | 5.7 |
| April | 17°C | 6°C | 109 mm | 12 | – | – | 6.5 |
| May | 23°C | 12°C | 122 mm | 13 | – | – | 7.1 |
| June | 27°C | 17°C | 112 mm | 12 | – | – | 7.3 |
| July | 29°C | 19°C | 97 mm | 11 | – | – | 7.6 |
| August | 28°C | 18°C | 89 mm | 10 | – | – | 7.8 |
| September | 25°C | 14°C | 79 mm | 8 | – | – | 8.0 |
| October | 18°C | 7°C | 78 mm | 9 | – | – | 7.3 |
| November | 10°C | 1°C | 68 mm | 9 | – | – | 5.9 |
| December | 3°C | -4°C | 56 mm | 8 | – | – | 4.5 |
Frequently asked questions
How hot is Ottawa in September?
Daytime highs average 25°C and nights about 14°C.
When is the best time to visit Ottawa?
The best months are September, August, July.