Climate Insights for Ottawa

The climate in Ottawa is cool. The average annual temperature is 7°C and approximately 1101mm of precipitation falls per year. Ottawa receives a notable amount of rainfall throughout the year, including during its driest month. Ottawa is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are January, February, December, when temperatures can drop to -13°C. Snowfall occurs from January to December, with around 157cm accumulating over the season.

Ottawa has a wide annual temperature range, spanning 40°C from the coldest to warmest months. The warmest month is July, when average highs reach 27°C and the mean temperature sits around 21°C. The coldest month is January, when overnight lows fall to -13°C and the daily average is -9°C. On average, daily temperatures fluctuate by about 10°C between overnight lows and afternoon highs. The sharpest temperature change occurs between April and May, with a 8°C shift in average temperatures.

Ottawa is a moderately rainy area, receiving approximately 1101mm of precipitation annually, which averages out to around 92mm per month. The wettest month is August, averaging 111mm of rainfall. October and July also tend to see above-average precipitation. The driest month is September, with just 71mm. That's 40mm less than August, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around. Snowfall is a regular feature from January to December, with around 157cm accumulating over the season. January typically sees the most snow at around 40cm.

Ottawa is mildly breezy, with an average annual wind speed of 16km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is April, averaging 18km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 14km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 4km/h between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 17km/h in winter, 17km/h in spring, 14km/h in summer, 16km/h in autumn.

It is currently spring in Ottawa, which began on March 20, 2026. Ottawa is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 27°C, while the coldest stretch bottoms out in January near -13°C. Summer is next, beginning on June 21, 2026 — 90 days from now.

The best time to visit Ottawa is during September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 16°C with modest rainfall averaging 71mm per month. By contrast, July can be uncomfortably hot with highs reaching 27°C, while January is the coldest period with lows dropping to -13°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Ottawa based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.