Weather and climate in Saint John (New Brunswick)

The climate of Saint John is continental, with very cold winters and mild or pleasantly warm summers.
The city is located on the southeastern coast of Canada, in New Brunswick, in the Bay of Fundy, beyond which is Nova Scotia.
We are in an area where there are continually clashes between the cold air masses coming down from the north of Canada and the milder ones coming from the Atlantic. For this reason, rains (and snowfalls for a few months of the year) are frequent. In addition, fog can form in the summer.
On the coldest days of the year, the temperature can drop to -25 °C (-13 °F) or even below. In January 2009, it dropped to -33.2 °C (-27.8 °F).
On the hottest days of the year, it can reach 30 °C (86 °F). In July 2013, it reached 33.7 °C (92.7 °F).
The average temperature of the coldest month (January) is of -7.6 °C (18.3 °F), that of the warmest month (July) is of 17.6 °C (64 °F). Here are the average temperatures.

Precipitation amounts to 1,295 millimeters (51 inches) per year: it is therefore quite abundant. It ranges from 80 mm (3.1 in) in the driest month (August) to 135 mm (5.3 in) in the wettest (November).
On average, 240 cm (94 in) of snow fall per year. Usually it snows from November to April.
Here is the average precipitation.

On average, there are around 1,945 sunshine hours per year. Here are the average sunshine hours per day.

The sea temperature ranges between 2 °C (36 °F) and 15 °C (59 °F). So, it is cold all year round. Here are the average sea temperatures.

Best Time

The best months to visit Saint John are July and August, as they are the mildest of the year.

Saint John - Weather by month

Based on the period 1991-2020

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January, the coldest month of the year, is generally a freezing cold month. The average temperature is of -7.6 °C (18 °F), with a minimum of -12.7 °C (9.1 °F) and a maximum of -2.5 °C (27.5 °F).
On the coldest nights of the month, the temperature usually drops to around -24.5 °C (-12.5 °F). However, it dropped to -33.2 °C (-27.8 °F) in January 2009.
On the warmest days of the month, the temperature usually reaches around 9 °C (48 °F). However, it reached 15 °C (59 °F) in January 2018.
Precipitation amounts to 125 mm (4.9 in), distributed over 16 days.
The day lasts on average 9 hours and 10 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 17 kph (11 mph).
The average sea temperature is of 4 °C (39 °F). Therefore, the sea is very cold for swimming.

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February is generally a freezing cold month. The average temperature is of -6.7 °C (20 °F), with a minimum of -11.8 °C (10.8 °F) and a maximum of -1.6 °C (29.1 °F).
On the coldest nights of the month, the temperature usually drops to around -24 °C (-11 °F). However, it dropped to -28.3 °C (-18.9 °F) in February 1992.
On the warmest days of the month, the temperature usually reaches around 7.5 °C (45.5 °F). However, it reached 15 °C (59 °F) in February 2016.
Precipitation amounts to 90 mm (3.5 in), distributed over 13 days.
The day lasts on average 10 hours and 25 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 70%. Hence, the air is normally humid.
The average wind speed is 17 kph (11 mph).
The average sea temperature is of 2.5 °C (36 °F). Therefore, the sea is very cold for swimming.

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March is generally a very cold month. The average temperature is of -2.2 °C (28 °F), with a minimum of -6.8 °C (19.8 °F) and a maximum of 2.5 °C (36.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -19.5 °C (-3 °F). However, it dropped to -28 °C (-18.4 °F) in March 2014.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 11.5 °C (52.5 °F). However, it reached 25.4 °C (77.7 °F) in March 2012.
Precipitation amounts to 110 mm (4.3 in), distributed over 14 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 40% of the time.
The average humidity is 69%.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 2 °C (35.5 °F). Therefore, the sea is very cold for swimming.

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April is generally a quite cold month. The average temperature is of 4.0 °C (39 °F), with a minimum of -0.9 °C (30.4 °F) and a maximum of 8.8 °C (47.8 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -8.5 °C (16.5 °F). However, it dropped to -17 °C (1.4 °F) in April 2015.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 17.5 °C (63 °F). However, it reached 22.3 °C (72.1 °F) in April 2016.
Precipitation amounts to 105 mm (4.1 in), distributed over 14 days.
The day lasts on average 13 hours and 35 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 41% of the time.
The average humidity is 69%.
The average wind speed is 17 kph (11 mph).
The average sea temperature is of 3 °C (37.5 °F). Therefore, the sea is very cold for swimming.

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May is generally a mild month. The average temperature is of 9.7 °C (49 °F), with a minimum of 4.2 °C (39.6 °F) and a maximum of 15.2 °C (59.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -3 °C (27 °F). However, it dropped to -6 °C (21.2 °F) in May 2015.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 24 °C (75.5 °F). However, it reached 33 °C (91.4 °F) in May 1992.
Precipitation amounts to 110 mm (4.3 in), distributed over 14 days.
The day lasts on average 14 hours and 55 minutes. So the days are long.
There are on average 6.5 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 15 kph (9 mph).
The average sea temperature is of 6 °C (42.5 °F). Therefore, the sea is very cold for swimming.

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June is generally a mild month. The average temperature is of 14.4 °C (58 °F), with a minimum of 8.8 °C (47.8 °F) and a maximum of 20 °C (68 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 1.5 °C (34.5 °F). However, it dropped to -1.8 °C (28.8 °F) in June 2018.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 28 °C (82.5 °F). However, it reached 31 °C (87.8 °F) in June 1997.
Precipitation amounts to 100 mm (3.9 in), distributed over 13 days.
The day lasts on average 15 hours and 35 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 7 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 10 °C (49.5 °F). Therefore, the sea is very cold for swimming.

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July, the warmest month of the year, is generally a very mild month. The average temperature is of 17.6 °C (64 °F), with a minimum of 12.2 °C (54 °F) and a maximum of 23 °C (73.4 °F).
On the coldest nights of the month, the temperature usually drops to around 6 °C (43 °F). However, it dropped to 2.3 °C (36.1 °F) in July 2012.
On the warmest days of the month, the temperature usually reaches around 29 °C (84.5 °F). However, it reached 33.7 °C (92.7 °F) in July 2013.
Precipitation amounts to 90 mm (3.5 in), distributed over 12 days.
The day lasts on average 15 hours and 10 minutes. So the days are long.
There are on average 7.5 hours of sunshine per day. So, the sun shines 48% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 13.5 °C (56.5 °F). Therefore, the sea is very cold for swimming.

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August is generally a very mild month. The average temperature is of 17.4 °C (63 °F), with a minimum of 11.9 °C (53.4 °F) and a maximum of 23 °C (73.4 °F).
On the coldest nights of the month, the temperature usually drops to around 4.5 °C (40.5 °F). However, it dropped to 0.4 °C (32.7 °F) in August 2004.
On the warmest days of the month, the temperature usually reaches around 29 °C (84 °F). However, it reached 33 °C (91.4 °F) in August 1993.
Precipitation amounts to 80 mm (3.1 in), distributed over 10 days.
The day lasts on average 14 hours and 0 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 15 °C (59 °F). Therefore, the sea is cold for swimming.

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September is generally a mild month. The average temperature is of 13.7 °C (57 °F), with a minimum of 8.5 °C (47.3 °F) and a maximum of 18.9 °C (66 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -0.5 °C (31 °F). However, it dropped to -4 °C (24.8 °F) in September 1995.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 26 °C (78.5 °F). However, it reached 33.3 °C (91.9 °F) in September 2010.
Precipitation amounts to 105 mm (4.1 in), distributed over 10 days.
The day lasts on average 12 hours and 30 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 49% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 13.5 °C (56.5 °F). Therefore, the sea is very cold for swimming.

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October is generally a quite mild month. The average temperature is of 8.1 °C (47 °F), with a minimum of 3.4 °C (38.1 °F) and a maximum of 12.8 °C (55 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -5 °C (23 °F). However, it dropped to -8.4 °C (16.9 °F) in October 2018.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 20.5 °C (69 °F). However, it reached 28.3 °C (82.9 °F) in October 2011.
Precipitation amounts to 115 mm (4.5 in), distributed over 12 days.
The day lasts on average 10 hours and 55 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 15 kph (10 mph).
The average sea temperature is of 11.5 °C (52.5 °F). Therefore, the sea is very cold for swimming.

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November is generally a cold month. The average temperature is of 2.6 °C (37 °F), with a minimum of -1.5 °C (29.3 °F) and a maximum of 6.8 °C (44.2 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -11 °C (12 °F). However, it dropped to -17 °C (1.4 °F) in November 1996.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 16 °C (60.5 °F). However, it reached 19.6 °C (67.3 °F) in November 2006.
Precipitation amounts to 135 mm (5.3 in), distributed over 14 days.
The day lasts on average 9 hours and 30 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 34% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 9 °C (48 °F). Therefore, the sea is very cold for swimming.

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December is generally a very cold month. The average temperature is of -3.2 °C (26 °F), with a minimum of -7.5 °C (18.5 °F) and a maximum of 1.1 °C (34 °F).
On the coldest nights of the month, the temperature usually drops to around -19 °C (-2 °F). However, it dropped to -27 °C (-16.6 °F) in December 1993.
On the warmest days of the month, the temperature usually reaches around 12 °C (53.5 °F). However, it reached 16.4 °C (61.5 °F) in December 2008.
Precipitation amounts to 130 mm (5.1 in), distributed over 16 days.
The day lasts on average 8 hours and 50 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 3.5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 17 kph (11 mph).
The average sea temperature is of 6 °C (43 °F). Therefore, the sea is very cold for swimming.