Is Ottawa hot in September?
Days are typically mild at 21.3°C, while nights average 10.5°C.
Canada · 1991–2020 normal
Ottawa in
September.
Typical September weather in Ottawa: 21.3°C by day, 10.5°C at night, 87 mm of rain over 9.3 wet days. These are measured 1991–2020 station normals, not a forecast.
Typical high21.3°C
Typical low10.5°C
Rain87 mm
Wet days9.3
In the year-round weather comparison, September scores 70 out of 100 (June leads the year at 81). Daylight is calculated as 12 h 28 from latitude 45.41°.
September at a glance
What is Ottawa like in September?
Plain answers from the measured climate record—not a forecast or a promise about a particular trip.
Does it rain much?
The measured monthly average is 87 mm across about 9 wet days.
How much daylight is there?
There are about 12 h 28 between sunrise and sunset at mid-month, calculated from the place latitude.
Is September a good time to visit?
September ranks 4 of 12 in our weather comparison; June ranks first.
The evidence behind this page
One month,
from the same station.
- Place identity
- GeoNames 6094817
- NOAA station
- CA006105976 · OTTAWA CDA
- Station distance
- 3.4 km from the place centre
- Coverage
- Strong coverage · 30 usable years
- Important limit
- Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.
Next step
Choose your month.
Then plan the details.
The weather comparison for Ottawa is based on climate evidence, not payments from travel companies. Flight, accommodation and activity links will be clearly labelled when they are added; there are no booking offers on this page today.
How travel partnerships will work