January Weather in Saint John, United States

Last updated: June 24, 2025

In Saint John, United States, the average temperature in January hovers around -3°C (27°F). During this chilly month, temperatures can plummet to a minimum of -30°C (-21°F), while occasionally reaching a maximum of 16°C (60°F). Expect about 70 mm (2.7 in) of precipitation over 9 days, along with an average humidity level of 82%, creating a crisp and moist winter atmosphere.

January Temperature in Saint John

In January in Saint John, the average temperature is -3°C (27°F), with maximums reaching 16°C (60°F) and minimums dropping as low as -30°C (-21°F). For travelers, this means it’s essential to prepare for a wide range of temperatures, from chilly days to surprisingly warm spells.

January Weather in Saint John: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Saint John, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Saint John, January typically has an average temperature of -3°C (27°F), with highs reaching up to 16°C (60°F) and lows dropping to around -30°C (-21°F).

Data source: Temperature data for Saint John generated using information from the Copernicus Climate Change Service.

January Precipitation in Saint John

In Saint John in January, the precipitation amount is 70 mm (2.7 in) over the course of 9 days.

January Precipitation Trends in Saint John

The chart displays monthly precipitation patterns in Saint John, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Saint John, January typically receives around 70 mm (2.7 inches) of precipitation spread over approximately 9 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in Saint John

In Saint John in January, humidity is 82%. With an average temperature of -3°C (27°F), this humidity feels like a biting chill that seeps into your bones, making traveling uncomfortable and necessitating extra layers to stay warm while navigating through the damp air.

January Average Humidity in Saint John

This chart illustrates the average monthly humidity levels in Saint John, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Saint John is approximately 82%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Saint John

In Saint John in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Saint John, you can check the information here.

Maximum UV Index Levels in Saint John for January

The chart shows the monthly maximum UV Index (UVI) for Saint John in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Saint John typically reaches 3, which falls under the moderate exposure category.

Data source: Saint John January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How January Weather in Saint John Compares to Other Months

Weather in Saint John varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Saint John, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Saint John, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-3°C (27°F)	70 mm (2.7 inches)	82%	moderate
February Weather	-2°C (29°F)	71 mm (2.8 inches)	83%	moderate
March Weather	4°C (39°F)	99 mm (3.9 inches)	84%	high
April Weather	9°C (48°F)	119 mm (4.7 inches)	85%	very high
May Weather	16°C (60°F)	162 mm (6.4 inches)	79%	very high
June Weather	22°C (71°F)	130 mm (5.1 inches)	82%	very high
July Weather	24°C (75°F)	103 mm (4.1 inches)	80%	very high
August Weather	23°C (73°F)	92 mm (3.6 inches)	81%	very high
September Weather	20°C (68°F)	74 mm (2.9 inches)	80%	very high
October Weather	13°C (56°F)	142 mm (5.6 inches)	82%	high
November Weather	5°C (40°F)	68 mm (2.7 inches)	88%	moderate
December Weather	1°C (34°F)	60 mm (2.4 inches)	84%	low