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.

10-year temperature averages for Ottawa, 2010 to 2019
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
30-year temperature averages for Ottawa, 1981 to 2010
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.

Days per month in Ottawa over 10, 20 or 30 °C
  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.

Average number of days with freezing temperatures in Ottawa
  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.

Days per month on average in Ottawa when the minimum temperature drops below -2, -10, or -20 °C
  -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.

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