January Weather in Boston, United States

Last updated: June 24, 2025

The average temperature in Boston, United States during January hovers around 5°C (41°F). Expect chilly days, with minimum temperatures dipping down to -9°C (16°F) and peaking at a comfortable 16°C (61°F). Rain might join the mix, as precipitation averages 94 mm (3.7 in) over 10 days. Plus, the air is quite moist, with an average humidity of 84%.

January Temperature in Boston

In January in Boston, the average temperature is 5°C (41°F), with maximums reaching 16°C (61°F) and minimums dropping as low as -9°C (16°F). Travelers should be prepared for chilly conditions, making warm clothing essential for exploring the area during this time.

January Weather in Boston: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Boston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Boston, January typically has an average temperature of 5°C (41°F), with highs reaching up to 16°C (61°F) and lows dropping to around -9°C (16°F).

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

January Precipitation in Boston

In Boston in January, the precipitation amount is 94 mm (3.7 in) over a duration of 10 days.

January Precipitation Trends in Boston

The chart displays monthly precipitation patterns in Boston, 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 Boston, January typically receives around 94 mm (3.7 inches) of precipitation spread over approximately 10 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 Boston

In Boston in January humidity is 84%. With an average temperature of 5°C (41°F), this humidity feels like a damp chill that seeps into your bones, making traveling uncomfortable as you navigate through the cold, heavy air that clings to your skin.

January Average Humidity in Boston

This chart illustrates the average monthly humidity levels in Boston, 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 Boston is approximately 84%, 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 Boston

In Boston 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 Boston, you can check the information here.

Maximum UV Index Levels in Boston for January

The chart shows the monthly maximum UV Index (UVI) for Boston 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 Boston typically reaches 3, which falls under the moderate exposure category.

Data source: Boston 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 Boston Compares to Other Months

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

This table compares monthly weather conditions in Boston, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	5°C (41°F)	94 mm (3.7 inches)	84%	moderate
February Weather	6°C (43°F)	119 mm (4.7 inches)	83%	moderate
March Weather	8°C (47°F)	87 mm (3.4 inches)	82%	high
April Weather	13°C (55°F)	86 mm (3.4 inches)	81%	very high
May Weather	17°C (64°F)	89 mm (3.5 inches)	80%	very high
June Weather	23°C (73°F)	73 mm (2.9 inches)	82%	very high
July Weather	26°C (79°F)	107 mm (4.2 inches)	81%	extreme
August Weather	26°C (78°F)	104 mm (4.1 inches)	81%	very high
September Weather	23°C (75°F)	105 mm (4.1 inches)	78%	very high
October Weather	19°C (67°F)	108 mm (4.2 inches)	80%	high
November Weather	12°C (54°F)	91 mm (3.6 inches)	84%	moderate
December Weather	8°C (47°F)	102 mm (4.0 inches)	84%	moderate