Ottawa Temperatures: Averages by Month
The numbers here tell you how hot and cold the weather usually is in Ottawa, Ontario during each month of the year.
The average high and low temperatures are listed below monthly and annually for the city, in both degrees Fahrenheit and Celsius.
Maximums and minimums are only part of the temperature picture. To fill in the rest, there's information on how many days a month get above or below a given temperature.
To find out how often it rises over 10, 20 or 30 °C each month in Ottawa, scroll down farther. There are also monthly and yearly counts of days with frost and cold weather.
The first set of high and low temperatures are averages for 2010 to 2019. Everything else here is based on 1981 to 2010 weather.
| High °F | Low °F | High °C | Low °C | |
|---|---|---|---|---|
| 23 | 8 | January | -5 | -13 |
| 25 | 9 | February | -4 | -13 |
| 37 | 21 | March | 3 | -6 |
| 52 | 34 | April | 11 | 1 |
| 69 | 48 | May | 20 | 9 |
| 75 | 56 | June | 24 | 13 |
| 82 | 61 | July | 28 | 16 |
| 79 | 59 | August | 26 | 15 |
| 72 | 52 | September | 22 | 11 |
| 57 | 41 | October | 14 | 5 |
| 42 | 28 | November | 6 | -2 |
| 30 | 18 | December | -1 | -8 |
| 54 | 36 | Year | 12 | 2 |
| High °F | Low °F | High °C | Low °C | |
|---|---|---|---|---|
| 22 | 6 | January | -6 | -14 |
| 26 | 9 | February | -3 | -13 |
| 36 | 20 | March | 2 | -7 |
| 53 | 35 | April | 11 | 1 |
| 66 | 46 | May | 19 | 8 |
| 75 | 56 | June | 24 | 13 |
| 80 | 60 | July | 27 | 16 |
| 78 | 58 | August | 25 | 14 |
| 69 | 50 | September | 20 | 10 |
| 55 | 39 | October | 13 | 4 |
| 42 | 29 | November | 5 | -2 |
| 28 | 15 | December | -2 | -9 |
| 53 | 35 | Year | 11 | 2 |
Days of Hot Weather in Ottawa
Ottawa usually has 12 days a year with temperatures in the low 30s Celsius. About twice a decade, a day heats up above 35 degrees Celsius (95 °F). The 30-degree weather can show up here anytime from June to September, and occasionally as early as April.
| 10 °C 50 °F |
20 °C 68 °F |
30 °C 86 °F | |
|---|---|---|---|
| January | 0 | 0 | 0 |
| February | 0 | 0 | 0 |
| March | 3 | 0 | 0 |
| April | 17 | 3 | 0 |
| May | 30 | 13 | 0 |
| June | 30 | 24 | 3 |
| July | 31 | 30 | 5 |
| August | 31 | 28 | 3 |
| September | 30 | 16 | 1 |
| October | 21 | 3 | 0 |
| November | 6 | 0 | 0 |
| December | 1 | 0 | 0 |
| Year | 199 | 117 | 12 |
When Ottawa Has Frosty Weather
Ottawa typically has 150 days a year when the minimum temperature is at 0 °C or below. The average date for the last frost in spring is April 29. Frost normally returns here on October 6. The frost-free period extends for 158 days on average between the final spring frost and the first fall frost.
| 0 °C 32 °F | |
|---|---|
| January | 30 |
| February | 27 |
| March | 26 |
| April | 12 |
| May | 1 |
| June | 0 |
| July | 0 |
| August | 0 |
| September | 0 |
| October | 6 |
| November | 19 |
| December | 29 |
| Year | 150 |
How Often Ottawa Has Cold Temperatures
Usually Ottawa's chilliest winter nights have temperatures in the minus-twenties Celsius (below -3 °F). The city averages 17 nights a year, most often in January, when the thermometer drops that low. Once every two or three years, the temperature plummets into the minus-thirties °C (less than -21 °F).
From November to April, it can remain below freezing here all day long. Ottawa typically has 74 frosty days a year.
| -2 °C 28 °F |
-10 °C 14 °F |
-20 °C -4 °F | |
|---|---|---|---|
| January | 29 | 21 | 8 |
| February | 25 | 18 | 5 |
| March | 22 | 9 | 1 |
| April | 6 | 0 | 0 |
| May | 0 | 0 | 0 |
| June | 0 | 0 | 0 |
| July | 0 | 0 | 0 |
| August | 0 | 0 | 0 |
| September | 0 | 0 | 0 |
| October | 2 | 0 | 0 |
| November | 12 | 2 | 0 |
| December | 25 | 13 | 3 |
| Year | 121 | 64 | 17 |
References
Environment Canada. Meteorological Service of Canada. Canadian Climate Normals. 1981-2010 Climate Normals & Averages.
Jay Lawrimore, Ron Ray, Scott Applequist, Bryant Korzeniewski, Matthew Menne. 2016. Global Summary of the Month and Year, Version 1.0. NOAA National Centers for Environmental Information.