Ottawa Weather in September

During September, Ottawa experiences high daytime temperatures of 27°C (81°F) and cooler nights around 14°C (57°F). Expect quite a bit of rainfall. Around 113 mm (4.4 in) is typical.

Rainfall in Ottawa in September

Typically, about 9 days will experience rainfall, with an average of 113 mm (4.4 in) for the month. When showers do arrive, they tend to be on the heavier side. Worth being prepared even if rain days are not that numerous.

Temperature in Ottawa in September

September in Ottawa brings typical temperatures with highs around 27°C (81°F) and lows of 14°C (57°F). This gives the month a fairly typical daily rhythm, with warmer afternoons and more comfortable nights. With lows of 14°C (57°F), nights are cool. If you're out after dark, an extra layer will keep you comfortable. The cooler air at night is also great for getting a good rest.

Sunshine in Ottawa in September

The city usually sees around 233 hours of sunlight, indicating many sunny days , a great month for sightseeing.

If you prefer dry days with pleasant temperatures, October typically offers the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.