January Weather in Saint John, United States

Last updated: June 24, 2025

In January, the average temperature in Saint John, United States hovers around 0°C (33°F). Expect minimums that can dip to -20°C (-3°F) and maximums reaching up to 21°C (69°F). During this month, the region typically experiences 25 mm (1.0 in) of precipitation over 3 days, contributing to an average humidity level of 75%. Prepare for a unique climate experience!

January Temperature in Saint John

In January in Saint John, the average temperature is 0°C (33°F). The maximum can reach 21°C (69°F), and the minimum can be as low as -20°C (-3°F). This wide range of temperatures means travelers should prepare for varying weather conditions.

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 0°C (33°F), with highs reaching up to 21°C (69°F) and lows dropping to around -20°C (-3°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 25 mm (1.0 in) over the course of 3 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 25 mm (1.0 inches) of precipitation spread over approximately 3 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

January Humidity in Saint John

In Saint John in January, humidity is 75%. With an average temperature of 0°C (33°F), this humidity feels like a cold, damp blanket enveloping you, making travel uncomfortable as you contend with the chill in the air and the moisture clinging to your skin.

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 75%, 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 reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Saint John for better planning.

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 4, 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	0°C (33°F)	25 mm (1.0 inches)	75%	moderate
February Weather	1°C (34°F)	21 mm (0.8 inches)	76%	moderate
March Weather	8°C (47°F)	68 mm (2.7 inches)	67%	high
April Weather	12°C (54°F)	50 mm (2.0 inches)	70%	very high
May Weather	18°C (65°F)	168 mm (6.6 inches)	82%	very high
June Weather	25°C (77°F)	62 mm (2.4 inches)	82%	extreme
July Weather	27°C (81°F)	58 mm (2.3 inches)	81%	extreme
August Weather	25°C (78°F)	74 mm (2.9 inches)	76%	very high
September Weather	23°C (73°F)	62 mm (2.4 inches)	67%	very high
October Weather	14°C (57°F)	81 mm (3.2 inches)	72%	high
November Weather	7°C (45°F)	24 mm (0.9 inches)	80%	moderate
December Weather	3°C (37°F)	32 mm (1.3 inches)	83%	moderate