Ottawa
Canada
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Ottawa, Canada

A view of The Parliament Hill from the Ottawa River in Ottawa, Canada
A view of The Parliament Hill from the Ottawa River in Ottawa, Canada
The first month of the autumn, September, is still a pleasant month in Ottawa, Canada, with average temperature varying between 20.2°C (68.4°F) and 10°C (50°F).

Temperature

In September, the average high-temperature marginally drops, from a warm 24°C (75.2°F) in August, to a pleasant 20.2°C (68.4°F). In September, in Ottawa, the average low-temperature is 10°C (50°F).

Humidity

In September, the average relative humidity in Ottawa is 80%.

Rainfall

The month with the least rainfall in Ottawa is September when the rain falls for 12.9 days and typically collects 54mm (2.13") of precipitation.

Snowfall

In Ottawa snow does not fall in June through September.

Daylight

In Ottawa, the average length of the day in September is 12.5h.

Sunshine

In Ottawa, the average sunshine in September is 8.8h.

UV index

The average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a medium health hazard from unsafe exposure to the UV radiation for average individuals.
Note: In September, the average maximum UV index of 3 translate into the following recommendations:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.

What is the temperature in September in Ottawa?

The average high-temperature, in September, in Ottawa, is 20.2°C (68.4°F), while the average low-temperature is 10°C (50°F).

What is the average humidity in September in Ottawa?

The average relative humidity in September is 80%.

How much does it rain in Ottawa in September?

In Ottawa, Canada, during September, the rain falls for 12.9 days and regularly aggregates up to 54mm (2.13") of precipitation.

What is the driest month in Ottawa?

The month with the least rainfall in Ottawa, Canada, is September when the rain falls for 12.9 days and typically collects 54mm (2.13") of precipitation.

Does it snow in Ottawa in September?

In Ottawa, in September, it doesn't snow. In October, it regularly snows.

When it does not snow in Ottawa?

June through September are months without snowfall.

How many hours of daylight does Ottawa have in September?

In September, the average length of the day in Ottawa is 12.5h.

How many hours of sunshine does Ottawa have in September?

In September, the average sunshine in Ottawa, Canada, is 8.8h.

What is the UV index intensity in September in Ottawa?

In Ottawa, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate health threat from unprotected exposure to the UV radiation.
Average temperature in September - Ottawa, Canada
  • Average high temperature in September: 20.2°C

The warmest month (with the highest average high temperature) is July (25.3°C).
The month with the lowest average high temperature is January (-6.3°C).

  • Average low temperature in September: 10°C

The month with the highest average low temperature is July (14.5°C).
The coldest month (with the lowest average low temperature) is January (-14.5°C).

Average humidity in September - Ottawa, Canada
  • Average humidity in September: 80%

Months with the highest relative humidity are January and February (91%).
The month with the lowest relative humidity is May (77%).

Average rainfall in September - Ottawa, Canada
  • Average rainfall in September: 54mm

The wettest month (with the highest rainfall) is October (78mm).
The driest month (with the lowest rainfall) is September (54mm).

Average rainfall days in September - Ottawa, Canada
  • Average rainfall days in September: 12.9 days

The month with the highest number of rainy days is July (17.1 days).
The month with the lowest number of rainy days is February (5.9 days).

Average snowfall in September - Ottawa, Canada
  • Average snowfall in September: 0mm

The month with the highest snowfall is January (321mm).
Months with the lowest snowfall are June, July, August and September (0mm).

Average snowfall days in September - Ottawa, Canada
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (19.8 days).
Months with the lowest number of snowfall days are June, July, August and September (0 days).

Average daylight in September / Average sunshine in September - Ottawa, Canada
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.6h).
The month with shortest days is December (Average daylight: 8.8h).

  • Average sunshine in September: 8.8h

The month with most sunshine is July (Average sunshine: 10.2h).
The month with least sunshine is February (Average sunshine: 2.8h).

Average UV index in September - Ottawa, Canada
  • Average UV index in September: 3

Months with the highest UV index are June, July and August (UV index 5).
Months with the lowest UV index are January, February, November and December (UV index 1).