Ottawa climate
Ottawa (Ontario, Canada) has a warm-summer humid continental climate (Köppen Dfb). The average temperature over the year is 6 °C43 °F, and about 981 mm39 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Ottawa climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | −621 | −163 | −1112 | 612.4 | 30 |
| Feb | −424 | −155 | −1014 | 552.2 | 28 |
| Mar | 235 | −817 | −326 | 652.5 | 29 |
| Apr | 1152 | 031 | 542 | 853.3 | 18 |
| May | 1966 | 745 | 1355 | 853.4 | 2 |
| Jun | 2474 | 1355 | 1865 | 1044.1 | 0 |
| Jul | 2679 | 1660 | 2170 | 983.9 | 0 |
| Aug | 2578 | 1558 | 2068 | 883.5 | 0 |
| Sep | 2271 | 1051 | 1661 | 873.4 | 0 |
| Oct | 1356 | 439 | 847 | 993.9 | 6 |
| Nov | 542 | −327 | 134 | 732.9 | 22 |
| Dec | −228 | −1113 | −620 | 803.2 | 30 |
| Year | 2679 | −163 | 643 | 98139 | 166 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 95% | 70% | 1.4 | 9:05 |
| Feb | 94% | 67% | 2.4 | 10:19 |
| Mar | 87% | 64% | 3.7 | 11:47 |
| Apr | 78% | 65% | 4.5 | 13:27 |
| May | 77% | 64% | 5.3 | 14:52 |
| Jun | 79% | 61% | 5.8 | 15:39 |
| Jul | 79% | 56% | 5.9 | 15:20 |
| Aug | 78% | 56% | 5.1 | 14:05 |
| Sep | 78% | 54% | 4.0 | 12:28 |
| Oct | 81% | 68% | 2.4 | 10:51 |
| Nov | 85% | 72% | 1.5 | 9:26 |
| Dec | 92% | 76% | 1.0 | 8:44 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Ottawa is like
The warmest month is July, with an average high of 26 °C79 °F and a low of 16 °C60 °F. The coldest is January, when highs average −6 °C21 °F and lows −16 °C3 °F. The climate is extremely continental — the average temperature swings by 31.9 °C57.4 °F between the coldest and the warmest month.
Annual precipitation is moderate at about 981 mm39 in. Rain is spread fairly evenly through the year. The wettest month is June (104 mm4.1 in), the driest is February (55 mm2.2 in).
Relative humidity ranges from 77% in May to 95% in January. The clearest skies (lowest average cloud amount, 54%) are typical of September. Average wind speed near the ground ranges from 1 km/h (1 mph) in June to 6 km/h (4 mph) in February. Daylight lasts from about 8.7 hours in December to 15.6 hours in June.
A lasting snow cover is typical in November–March, when the average snow depth in the reanalysis exceeds 10 cm (deepest in February, about 21 cm).
Best time to visit Ottawa
Based on these averages, the most comfortable months for sightseeing and outdoor activities are June and August and September: average highs of 22 °C71 °F to 25 °C78 °F with 87 mm3.4 in to 104 mm4.1 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of −6 °C21 °F.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Ottawa
- Winter (December–February) — highs −621 to −2 °C28 °F, lows −163 to −11 °C13 °F, about 66 mm2.6 in of precipitation a month. Pack a winter coat, hat, gloves and warm, non-slip boots.
- Spring (March–May) — highs 235 to 19 °C66 °F, lows −817 to 7 °C45 °F, about 78 mm3.1 in of precipitation a month. Pack a warm coat, layers and closed shoes, an extra layer for the cooler mornings and evenings and shoes with good grip, as frost is common.
- Summer (June–August) — highs 2474 to 26 °C79 °F, lows 1355 to 16 °C60 °F, about 97 mm3.8 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
- Autumn (September–November) — highs 542 to 22 °C71 °F, lows −327 to 10 °C51 °F, about 86 mm3.4 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket.
How Ottawa compares
Compared with Montréal, about 165 km to the east, Ottawa is on average 0.9 °C1.5 °F warmer and receives 10% less precipitation (981 mm39 in vs 1,086 mm43 in). The difference is largest in January (1.4 °C2.5 °F warmer).
Of the 40 places in Canada covered by World Climates, Ottawa is the 26th warmest by annual mean temperature and the 15th wettest by annual precipitation. See all of them on the Canada climate page.
Places in other countries with the most similar temperature and rainfall pattern: Asahikawa (Japan, Dfb), Yelets (Russia, Dfb) and Obihiro (Japan, Dfb).
The same NASA POWER grid cell also contains Gatineau (pop. 300,045), Nepean (pop. 180,000), Gloucester (pop. 150,012), Orléans (pop. 125,937) and Ottawa South (pop. 125,090). Their long-term averages in this dataset are essentially the same as for Ottawa, so they do not have separate pages.
Nearby places
- Kingston 145 km · 9 °C48 °F · 942 mm37 in
- Montréal 165 km · 5 °C41 °F · 1,086 mm43 in
- Trois-Rivières 265 km · 5 °C41 °F · 1,054 mm42 in
- Syracuse 265 km · 9 °C49 °F · 1,110 mm44 in
- Rochester 294 km · 9 °C49 °F · 948 mm37 in
- Sherbrooke 297 km · 6 °C42 °F · 1,135 mm45 in
- Oshawa 301 km · 9 °C47 °F · 719 mm28 in
- Ajax 316 km · 9 °C48 °F · 719 mm28 in
Frequently asked questions
What is the warmest month in Ottawa?
July is the warmest month in Ottawa, with an average high of 26 °C (79 °F) and an average low of 16 °C (60 °F).
What is the coldest month in Ottawa?
January is the coldest month, with an average high of -6 °C (21 °F) and an average low of -16 °C (3 °F).
When does it rain the most in Ottawa?
June is the wettest month with about 104 mm (4.1 in) of precipitation; February is the driest with about 55 mm (2.2 in).
What is the best time to visit Ottawa?
Judging by long-term averages, the most comfortable months are June and August and September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 124 m, while Ottawa lies at about 71 m. Temperatures on this page were therefore adjusted by +0.3 °C0.6 °F using the standard lapse rate of 6.5 °C per 1,000 m.