Weather in Ottawa in September 2024
Average weather
Average temperature in Ottawa in September
The temperature in September is +68°F on average, with a range between a maximum of +82°F during the day and a minimum of +37°F at night.
The average maximum temperature goes up 0% by the end of the month, compared with the beginning of the month, from +64°F to +64°F.
Is Ottawa warm or cold in September?
Ottawa is typically mild in September.
Maximum temperatures go down compared to the previous month from +77°F to +70°F. The minimum temperature also goes down from +59°F to +50°F.
Pack a light jacket as it will be warm in the day and cool in the evenings.
Take a look at how September is compared to other months in Ottawa:
Climate in Ottawa in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +77°F | +70°F | +55°F | ||||
| Min. temperature | ||||||
| +39°F | +27°F | +18°F | ||||
| Max. temperature | ||||||
| +97°F | +95°F | +82°F | ||||
| Rainfall | ||||||
| 84 mm | 90 mm | 89 mm | ||||
| Wind | ||||||
| 2 m/s | 2 m/s | 2 m/s | ||||
| Humidity | ||||||
| 72% | 75% | 75% | ||||
| Air pressure | ||||||
| 1014 HPa | 1015 HPa | 1015 HPa | ||||
| Sunny days | ||||||
| 4 | 5 | 3 | ||||
| Cloudy days | ||||||
| 20 | 18 | 19 | ||||
| Rainy days | ||||||
| 7 | 7 | 8 | ||||
| Snowy days | ||||||
| 0 | 0 | 1 | ||||
September weather is still as good as in August. It’s getting colder in September. From +77°F in the day, the average maximum temperature lowers to +70°F. Prepare for more rain. Average rainfall goes from 84 mm to 90 mm. Humidity rises from 72% to 75%. The average wind speed doesn’t change much during September, staying around 2 m/s. The good news is there are likely to be more sunny days in September, from 4 to 5.
Next month (October) brings a further decline in the weather.
Wind
The average wind speed is 3 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Ottawa is gradually decreasing during September, going from 5 m/s to 1 m/s over the course of the month.
Rain
How was the weather last September in Ottawa?
Climate Change Over the Years
The climate in Ottawa in September has not changed that much over the last 43 years.
The average temperature was the lowest in 1986 (+66°F) and the highest in 2002 (+77°F). The driest year was 1984 with only 42 mm of rainfall, and the wettest year was 1986 with 218 mm.
FAQ
Is September a good time to visit Ottawa?
Can you sunbathe in Ottawa in September?
Is Ottawa rainy in September?
Is it sunny in Ottawa in September?
Other cities in Canada
Monthly weather in Ottawa
Source of the data
For this page, we’ve looked at the typical weather in Ottawa, based on historical hourly weather data from January 1, 1979, to December 31, 2022.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.