Saint John NB Average Temperatures 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.

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 Saint John, 2010 to 2019
High °F	Low °F		High °C	Low °C
29	10	January	-2	-12
30	10	February	-1	-12
37	17	March	3	-8
49	30	April	9	-1
60	38	May	16	4
68	46	June	20	8
75	53	July	24	12
74	52	August	24	11
68	46	September	20	8
57	37	October	14	3
44	27	November	7	-3
35	17	December	1	-8
52	32	Year	11	0

30-year temperature averages for Saint John, 1981 to 2010
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

The chilliest winter nights at Saint John 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

Saint John NB Temperatures: Averages by Month

Days of Hot Weather in Saint John

When Saint John Has Frosty Weather

How Often Saint John Has Cold Temperatures

References

More on Weather in New Brunswick