CanadaAverage weather for Ottawa in August
It's warm in August in Ottawa with an average temperature of 25°C. Temperatures this month range from a low of 22°C to a high of 28°C. At night, you can expect temperatures between 14°C and 18°C.
Start of August
The month of August starts in Ottawa with warm temps, averaging around 26°C during the day and nights around 17°C. You can expect regular precipitation, but there will also be some sunny days in the early part of the month.
With the temperature difference between day and night, it’s smart to wear layers.
Mid August
By mid-August, daytime temps drop to around 25°C, with nights around 16°C. There’s a high chance of precipitation during this time.
End of August
By the end of August, the average daytime temperature in Ottawa is around 25°C, while nighttime temps are about 16°C. Expect regular precipitation, but if you’re lucky, you’ll also get some dry and sunny days.
In August, there is an average of 196 mm of precipitation, spread over 9 days. The wind speed is around 3 Bft, mostly coming from the Southwest.
Ottawa in August |
New York | ||
|---|---|---|---|
 Average temperature |
25°C | 30°C | |
 Max. temperature |
28°C | 31°C | |
| Min. temperature |
22°C | -5°C | |
 Total precipitation |
196 mm | 79 mm | |
| Rainy days |
9 days | 13 days | |
July
UV index
The UV index is a maximum of 7 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Is August a good time to visit Ottawa?
Looking for sun? August isn’t a good month to be in Ottawa. The temperature is nice, but there’s too much chance of rain.
Temperature records
With 34°C in 2016, Ottawa reached the highest temperature in August over the past 10 years. The lowest daytime temperature in this month was 14°C in 2023. The extreme nighttime temperatures ranged from a lowest recorded value of 8°C to a highest value of 23°C.
Check out the climate of Ottawa for all months and discover the best travel time
Curious about the weather in other parts of Canada? Check out the climate and weather for spots like Vancouver, Toronto, Niagara Falls, or explore other destinations in Canada.
Daily Temperature in August in Ottawa
This chart shows the average daily high and low temperatures in August for Ottawa, in degrees Celsius. The red line represents the highs, and the blue line shows the lows. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, provide the average temperatures for this month.
Daily Precipitation in August in Ottawa
The chart below shows the average daily precipitation in August for Ottawa, measured in millimeters over the past few years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are listed at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that it rained more often. But remember, it’s just an average, and every day can be different. Based on historical weather data for August, you can expect about 9 days of precipitation in Ottawa.
Daily UV index in August in Ottawa
This chart shows the average daily UV index in August in Ottawa, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in August in Ottawa over the years
This chart shows the average temperature in August in Ottawa, measured in degrees Celsius, over the past few years.
Total precipitation in August in Ottawa over the years
This chart shows the average precipitation in August in Ottawa, measured in millimeters over the past years. Precipitation is always measured as water, whether it’s snow or hail.
Daily weather in August for Ottawa
Click on any day in August to get detailed info about the usual weather on that day in Ottawa. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in August in Ottawa
Have you been to Ottawa in August?
Share your weather experience in August in Ottawa.
Average weather in Ottawa by month
Click on a month below to see detailed weather info for Ottawa. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
