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Monthly climate in Saint John, Canada

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Saint John features a humid continental climate (Dfb). Temperatures typically range between -4 °C (26 °F) and 17 °C (63 °F) through the year, but rarely can drop to -22 °C (-8 °F) or can rise to as high as 23 °C (74 °F). The average annual precipitation amounts to about 1403 mm (55.2 inches) and receives 139 rainy days on the 1 mm (0.04 inches) threshold annually. Saint John enjoys an average of 2787 hours of sunshine throughout the year, and daylight varies from 8 hours 46 minutes to 15 hours 34 minutes per day.

Monthly average temperatures in Saint John, Canada

The warmest months in Saint John are July, August and September, with daily mean temperatures ranging from 15 to 17 °C (59 - 63 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -4 to -1 °C (26 - 31 °F) throughout the day. On average each year, Saint John experiences 0 days above 25 °C (77.0 °F) and 109 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Saint John. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum13°C
(56°F)		10°C
(50°F)		11°C
(52°F)		13°C
(55°F)		20°C
(68°F)		21°C
(71°F)		22°C
(72°F)		23°C
(74°F)		22°C
(73°F)		19°C
(67°F)		16°C
(62°F)		14°C
(57°F)
Mean maximum9°C
(49°F)		7°C
(45°F)		8°C
(47°F)		12°C
(53°F)		17°C
(64°F)		20°C
(67°F)		21°C
(71°F)		22°C
(73°F)		20°C
(69°F)		18°C
(64°F)		15°C
(60°F)		13°C
(55°F)
Average high0°C
(32°F)		0°C
(33°F)		2°C
(36°F)		7°C
(45°F)		11°C
(53°F)		15°C
(60°F)		18°C
(65°F)		20°C
(67°F)		17°C
(63°F)		13°C
(56°F)		7°C
(45°F)		2°C
(36°F)
Daily mean-4°C
(26°F)		-3°C
(26°F)		-1°C
(31°F)		4°C
(40°F)		9°C
(48°F)		13°C
(56°F)		16°C
(62°F)		17°C
(63°F)		15°C
(59°F)		11°C
(52°F)		5°C
(40°F)		-1°C
(31°F)
Average low-7°C
(19°F)		-7°C
(19°F)		-4°C
(26°F)		2°C
(36°F)		6°C
(44°F)		11°C
(51°F)		14°C
(58°F)		15°C
(60°F)		13°C
(55°F)		8°C
(48°F)		2°C
(36°F)		-4°C
(25°F)
Mean minimum-17°C
(1°F)		-17°C
(1°F)		-14°C
(7°F)		-2°C
(28°F)		2°C
(37°F)		7°C
(44°F)		12°C
(53°F)		12°C
(54°F)		9°C
(48°F)		3°C
(38°F)		-6°C
(21°F)		-13°C
(9°F)
Minimum-22°C
(-8°F)		-20°C
(-4°F)		-17°C
(2°F)		-5°C
(23°F)		1°C
(33°F)		4°C
(39°F)		11°C
(51°F)		11°C
(53°F)		7°C
(45°F)		0°C
(33°F)		-12°C
(10°F)		-18°C
(-1°F)

Compare climate in Saint John with other places

Compare temperature, precipitation, sunshine, UV index in Saint John, Canada with other places around the world.

Monthly average precipitation in Saint John, Canada

Saint John usually has the most precipitation in April, November and December, with an average of 13 rainy days and 152 mm (6.0 inches) of precipitation per month. The driest months in Saint John are March, July and August. On average, 90 mm (3.5 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Saint John. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)107 (4.2)112 (4.4)88 (3.5)129 (5.1)117 (4.6)110 (4.3)92 (3.6)89 (3.5)108 (4.3)123 (4.8)184 (7.3)142 (5.6)
Average precipitation days (≥ 1 mm)101210131211131010121412

Monthly sunshine hours in Saint John, Canada

The sunniest months in Saint John are June, July and August, when the sun shines an average of 10 hours 2 minutes a day. Least sunny months in Saint John: January, November and December receive an average of 4 hours 46 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Saint John. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours126186242227280307303312266221159153
Mean daily daylight hours9h 10m10h 24m11h 57m13h 32m14h 53m15h 34m15h 12m13h 59m12h 28m10h 53m9h 30m8h 46m

Solar UV radiation in Saint John, Canada

Saint John experiences the highest level of ultraviolet (UV) radiation in May, June and August, when the maximum UV index can reach values of 8 - 10, which corresponds to the Very High category of sun exposure. January, February and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Saint John UV Index data.

Average daily maximum UV levels by month for Saint John. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)2357910887532