Boston Weather in January
January brings the year's coldest and snowiest weather to Boston, Massachusetts.
This page gives detailed information on the typical January temperature, precipitation, sun, humidity, wind and storms for Boston. The numbers here are historical averages based on climate data gathered at Boston's Logan International Airport, located on the waterfront next to Boston Harbor.
|37 °F||January average high||3 °C|
|23 °F||January average low||-5 °C|
January is the coldest month overall for Boston and the 19th to 27th are its chilliest days. They have daily highs averaging 36 degrees Fahrenheit (2 degrees Celsius) and the lows of 22 °F (-6 °C).
|12 days||40 °F max. or more (4 °C)|
|12 days||20 °F min. or less (-8 °C)|
Boston averages 4 days in January when the thermometer reaches into the 50s °F (over 10 °C). Temperatures above 60 °F (16 °C) happen occasionally, although not every year. Typically on ten days the mercury remains below freezing for the entire day.
At night, the thermometer dips to 10 °F (-12 °C) or below on 4 days. But most years, January does not get temperatures as cold as 0 °F (-18 °C).
|3.4 in||total precipitation||86 mm|
|12 days||of rain or snowfall|
Half the time, Boston receives 2.6 to 4.4 inches (66 to 113 mm) of precipitation in January. One in four years has drier weather, while another one in four is wetter.
|14.3 in||total snowfall||36 cm|
|7 days||with new snow|
January's snowfall varies a lot from year to year in Boston. Between 5 and 18 inches (13 to 45 cm) of fresh snow arrives in half the years. Less new snow lands in one out of four Januaries, while another twenty-five percent are snowier.
|9 days||clear skies|
The sun's rays reach the ground in Boston during 53 percent of daylight hours on average in January, for a total of 155 hours in the month. Typically on 9 days this month the sky is mainly clear, with at most 30 percent cloud cover.
Sunlight in January at Boston lasts for 9 hours and 29 minutes a day on average. The shortest day of the month is the 1st with 9 hours and 9 minutes of daylight. By the end of the month, the days have lengthened to 9:58 from sunrise to sunset. These durations of daylight can vary by a minute or two from year to year.
|62 %||January average humidity|
The relative humidity in Boston during January usually peaks at 67 percent in the morning then drops to 57 percent by early afternoon.
|Local Time||1 am||4 am||7 am||10 am||1 pm||4 pm||7 pm||10 pm|
|13.6 mph||January wind speed average||21.9 kph|
January is a little windier than most other months in Boston.
|1 day||snowfall of 5 inches (13 cm) or more|
|0 days||with thunderstorms in January|
Boston has a total of 4 days this month when it snows at least an inch (2.5 cm), more often than any other month.
About once in five years, a January thunderstorm passes over Boston.
The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals.