Saint John NB Temperatures: Averages by Month





The numbers here tell you how hot and cold the weather usually is in Saint John, New Brunswick during each month of the year.

The average high and low temperatures are listed below monthly and annually for Saint John, 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 or 20 °C each month in Saint John, scroll down farther. There are also monthly and yearly counts of days with frost and cold weather.

All the numbers are long-term historical averages based on climate data gathered from 1981 to 2010.

Average Saint John temperatures
High °F Low °F   High °C Low °C
28 8 January -2 -13
29 9 February -2 -13
36 19 March 2 -7
47 30 April 9 -1
59 39 May 15 4
67 47 June 20 8
73 53 July 23 12
72 52 August 22 11
65 46 September 18 8
54 37 October 12 3
44 29 November 6 -2
33 15 December 1 -9
51 32 Year 10 0

Days of Hot Weather in Saint John

A hot day at St John means highs in the twenties Celsius. Most summer days here get that warm, along with a few in spring and fall. The thermometer can nudge above 30 °C (86 °F), but that happens only for one day a year on average.

Days per month in Saint John above 10 or 20 °C
  10 °C
50 °F
20 °C
68 °F
January 1 0
February 0 0
March 2 0
April 11 0
May 27 4
June 30 14
July 31 24
August 31 23
September 30 8
October 22 1
November 7 0
December 2 0
Year 194 75

When Saint John Has Frosty Weather

Saint John typically has 167 days a year when the minimum temperature is at 0 °C or below. The average date for the last frost in spring is May 16. Frost normally returns here on October 2. The frost-free period extends for 138 days on average between the final spring frost and the first fall frost.

Average number of days with freezing temperatures in Saint John
  0 °C
32 °F
January 30
February 27
March 28
April 20
May 5
June 0
July 0
August 0
September 1
October 10
November 19
December 28
Year 167

How Often Saint John Has Cold Temperatures

Saint John's chilliest winter nights have lows in the minus-twenties °C (below -3 °F). The city averages just 14 nights a year, mostly in January and February, when the thermometer drops that low. Temperatures less than -30 °C (-22 °F) can occur, but typically only once or twice in ten years.

From November to April, it can remain below freezing here all day long. Saint John typically has 61 days a year when the temperature never rises above 0 °C.

Days per month on average in Saint John 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 6
February 25 19 4
March 24 10 1
April 12 0 0
May 1 0 0
June 0 0 0
July 0 0 0
August 0 0 0
September 0 0 0
October 4 0 0
November 15 2 0
December 26 14 2
Year 135 66 14
Reference

Environment Canada. Meteorological Service of Canada. Canadian Climate Normals. 1981-2010 Climate Normals & Averages.

New Brunswick Temperatures
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