Boston Weather in December

Boston, Massachusetts usually experiences its first truly wintery weather of the season in December. Winter's first snowstorms arrive and so do days when the temperature remains below freezing.

This page gives detailed information on the typical December weather for Boston.

You can jump directly to data and descriptions for:

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.

Temperature Weather iconTemperature

41 °F December average high 5 °C
28 °F December average low -2 °C

In most years, Boston averages a daily maximum temperature for December that's between 37 and 45 degrees Fahrenheit (3 to 7 degrees Celsius). The minimum temperature usually falls between 24 and 32 °F (-4 to 0 °C).

The days at Boston cool rapidly during December. By the end of the month, the temperature has dropped over 9 °F (5 °C) below what it was at the start.

17 days 40 °F max. or more (4 °C)
21 days 32 °F min. or less (0 °C)

Boston averages 1 day in December when the thermometer reaches into the 60s °F (over 15 °C). A temperature above 70 °F (21 °C) in December has happened about once a decade. Typically on 5 days the mercury remains below freezing for the entire day.

December has one night on average when the thermometer dips to 10 °F (-12 °C) or below. But the weather does not normally get as cold as 0 °F (-18 °C).

Rainy Weather iconPrecipitation

3.8 in total precipitation 96 mm
12 days of rain or snowfall

Half the time, Boston receives 2 to 5 inches (54 to 135 mm) of precipitation in December. One in four years has drier weather, while another one in four is wetter.

Snowy Weather iconSnow

9.0 in total snowfall 22.9 cm
5 days with new snow

December's snowfall varies a lot from year to year in Boston. Between 3 and 12 inches (9 to 29 cm) of fresh snow arrives in half the years. Less new snow lands in one out of four Decembers, while another twenty-five percent are snowier.

Boston typically has at least an inch (2.5 cm) of snow on the ground for 5 days this month. The snow normally accumulates to 5 inches (13 cm) or deeper on 2 days.

Sunny Weather iconSun

52 % sunshine
9 days clear skies

The sun's rays reach the ground in Boston during 52 percent of daylight hours on average in December, for a total of 147 hours in the month. Typically on 9 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in December at Boston lasts for 9 hours and 8 minutes a day on average. The shortest days of the year, from around December 18th to 24th, last 9 hours and 5 minutes from sunrise to sunset.

Humid Weather iconHumidity

65 % December average humidity

The relative humidity in Boston during December usually peaks at 71 percent in the morning then drops to 59 percent by early afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 68 70 71 65 59 60 64 66

Windy Weather iconWind

13.2 mph December wind speed average 21.2 kph

December is a little windier than most other months in Boston.

Stormy Weather iconStorms

1 day snowfall of 3 inches (8 cm) or more
0 days with thunderstorms in December

The first substantial snowfalls of winter for Boston usually arrive in December.

About once in five years, a December thunderstorm passes over Boston.

Reference

These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity and thunderstorm statistics are 1961-1990 normals.

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