August weather forecast
Ottawa, Canada

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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

Weather in August

As August strolls into Ottawa, it carries the last hints of summer along. There's a slight slip in temperatures from July's peak, yet the weather remains hospitable for outdoor activities. Despite the impending arrival of autumn, August keeps up the summer spirit with its warm days and balmy nights. It is during this time of the year that Ottawa experiences a fine blend of summer's warmth and autumn's cool.

Temperature

As Ottawa, Canada, welcomes August, the average high-temperature stabilizes at a still warm 24°C (75.2°F), showing little deviation from July's 25.3°C (77.5°F). During the month of August, an average temperature of 13.7°C (56.7°F) is noted during the nights.

Humidity

In Ottawa, the average relative humidity in August is 81%.

Rainfall

In Ottawa, in August, during 15.9 rainfall days, 68mm (2.68") of precipitation is typically accumulated. In Ottawa, during the entire year, the rain falls for 149.6 days and collects up to 772mm (30.39") of precipitation.

Snowfall

In Ottawa, snow does not fall in June through September.

Daylight

The average length of the day in August in Ottawa is 14h and 3min.
On the first day of the month, sunrise is at 5:47 am and sunset at 8:30 pm. On the last day of August, sunrise is at 6:23 am and sunset at 7:41 pm EDT.

Sunshine

The average sunshine in August is 9.9h.

UV index

June through August, with an average maximum UV index of 5, are months with the highest UV index in Ottawa. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: The average daily UV index of 5 in August transforms into the following instructions:
Make use of precautions - Suggestions to resist sunburn are communicated. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.

Frequently asked questions

What are the temperatures in Ottawa in August?

The average high-temperature, in August, in Ottawa, is 24°C (75.2°F), while the average low-temperature is 13.7°C (56.7°F).

What is the average humidity in August in Ottawa?

The average relative humidity in August in Ottawa, Canada, is 81%.

How many days does it rain in August in Ottawa?

In Ottawa, during August, the rain falls for 15.9 days and regularly aggregates up to 68mm (2.68") of precipitation.

When it does not snow in Ottawa?

June through September are months without snowfall in Ottawa.

How many hours of daylight does Ottawa have in August?

In August, the average day length in Ottawa is 14h and 3min.

What time are sunrise and sunset in August in Ottawa?

On the first day of August in Ottawa, Canada, sunrise is at 5:47 am and sunset at 8:30 pm. On the last day of the month, sunrise is at 6:23 am and sunset at 7:41 pm EDT.

How many hours of sunshine does Ottawa have in August?

The average sunshine duration in August is 9.9h.

What are the months with the highest UV index in Ottawa?

The months with the highest UV index in Ottawa are June through August, with an average maximum UV index of 5.

How high is the UV index in August in Ottawa?

The average daily maximum UV index in August is 5. A UV Index estimate of 3 to 5 represents a medium health risk from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Ottawa, Canada

Average temperature in August - Ottawa, Canada
  • Average high temperature in August: 24°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 August: 13.7°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 pressure in August
Ottawa, Canada

Average pressure in August - Ottawa, Canada
  • Average pressure in August: 1014.1mbar

The month with the highest atmospheric pressure is March (1018mbar).
The month with the lowest atmospheric pressure is June (1012.5mbar).

Average wind speed in August
Ottawa, Canada

Average wind speed in August - Ottawa, Canada
  • Average wind speed in August: 10km/h

The windiest month (with the highest average wind speed) is April (14km/h).
The calmest month (with the lowest average wind speed) is July (9.8km/h).

Average humidity in August
Ottawa, Canada

Average humidity in August - Ottawa, Canada
  • Average humidity in August: 81%

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

Average rainfall in August
Ottawa, Canada

Average rainfall in August - Ottawa, Canada
  • Average rainfall in August: 68mm

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

Average rainfall days in August
Ottawa, Canada

Average rainfall days in August - Ottawa, Canada
  • Average rainfall days in August: 15.9 days

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

Average snowfall in August
Ottawa, Canada

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

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

Average snowfall days in August
Ottawa, Canada

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

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

Average daylight in August /
Average sunshine in August
Ottawa, Canada

Average daylight in August / Average sunshine in August - Ottawa, Canada
  • Average daylight in August: 14h and 0min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in August: 9h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is February (Average sunshine: 2h and 48min).

Average sunshine days in August
Ottawa, Canada

Average sunshine days in August - Ottawa, Canada
  • Average sunshine days in August: 13.2 days

The month with the most sunshine days is September (15 days).
The month with the least sunshine days is February (9.1 days).

Average UV index in August
Ottawa, Canada

Average UV index in August - Ottawa, Canada
  • Average UV index in August: 5

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

Average cloud cover in August
Ottawa, Canada

Average cloud cover in August - Ottawa, Canada
  • Average cloud cover in August: 34

The months with the most cloud cover are January and February (Cloud cover 69).
The month with the least cloud cover is July (Cloud cover 32).

Average visibility in August
Ottawa, Canada

Average visibility in August - Ottawa, Canada
  • Average visibility in August: 9km

The months with the highest visibility are April, May, June, July, August and October (9km).
The months with the lowest visibility are January and February (7km).

Ottawa, Canada

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