December weather forecast
Cambridge, MA

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The John Weeks Memorial Footbridge in Cambridge, Massachusetts, over the Charles River calm waters, and a distant view of the Havard University student residence unit
The John Weeks Memorial Footbridge in Cambridge, Massachusetts, over the Charles River calm waters, and a distant view of the Havard University student residence unit

Weather in December

December marks the onset of winter in Cambridge, Massachusetts. White-covered landscapes and Christmas decorations create a picturesque ambiance. The winter chill can be felt, but snowfall remains at the lower end, making travel less challenging. The temperatures drop further across this month with parameters from 29.3°F (-1.5°C) to 39.6°F (4.2°C). Despite the cold, the festive spirit with glowing lights and holiday markets is heart-warming.

Temperature

December comes with a drop in the average high-temperature, falling from November's frosty 49.5°F (9.7°C) to an icy 39.6°F (4.2°C). Cambridge, in December, witnesses an average low-temperature of 29.3°F (-1.5°C).

Humidity

In December, the average relative humidity is 76%.

Rainfall

In Cambridge, in December, during 5.6 rainfall days, 0.55" (14mm) of precipitation is typically accumulated. In Cambridge, during the entire year, the rain falls for 81.8 days and collects up to 5.51" (140mm) of precipitation.

Snowfall

Months with snowfall are January through May, November and December. December is the month with the most snowfall. Snow falls for 2.7 days and accumulates 0.71" (18mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9h and 6min of daylight.
On the first day of December, sunrise is at 6:54 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:21 pm EST.

Sunshine

The average sunshine in December is 4.9h.

UV index

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The maximum UV index, 2 during December, leads to the following recommendations:
While most people are not greatly affected by extended sun exposure, those with fair skin, babies, and children must always have protection. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.
Updated: Aug 31, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold does it get in December?

The average high-temperature and low-temperature in Cambridge, Massachusetts, during December are 39.6°F (4.2°C) and 29.3°F (-1.5°C) respectively. In July, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which factors the actual air temperature with the relative humidity, is calculated to be 86°F (30°C).

What is the average humidity in December?

In December, the average relative humidity is 76%.

How many days does it rain in December?

In December, the rain falls for 5.6 days. Throughout December, 0.55" (14mm) of precipitation is accumulated.

When does it snow the most?

The month with the most snowfall is December, when snow falls for 2.7 days and typically aggregates up to 0.71" (18mm) of snow.

How many days does it snow in December in Cambridge?

In Cambridge, in December, during 2.7 snowfall days, 0.71" (18mm) of snow is typically accumulated.

What is the month with the shortest days?

With an average of 9h and 6min of daylight, December has the shortest days of the year.

How many hours of daylight does Cambridge have in December?

The average day length in December is 9h and 8min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 6:54 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:21 pm EST.

How many hours of sunshine does Cambridge have in December?

The average sunshine duration in December is 4.9h.

When is the lowest UV index?

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2.

How high is the UV index in December?

In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Cambridge, MA

Average temperature in December - Cambridge, MA
  • Average high temperature in December: 39.6°F

The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (33.8°F).

  • Average low temperature in December: 29.3°F

The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).

Average pressure in December
Cambridge, MA

Average pressure in December - Cambridge, MA
  • Average pressure in December: 30.03"Hg

The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Cambridge, MA

Average wind speed in December - Cambridge, MA
  • Average wind speed in December: 9mph

The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is August (6mph).

Average humidity in December
Cambridge, MA

Average humidity in December - Cambridge, MA
  • Average humidity in December: 76%

The months with the highest relative humidity are January and February (77%).
The month with the lowest relative humidity is April (69%).

Average rainfall in December
Cambridge, MA

Average rainfall in December - Cambridge, MA
  • Average rainfall in December: 0.55"

The wettest month (with the highest rainfall) is November (0.63").
The driest month (with the least rainfall) is September (0.2").

Average rainfall days in December
Cambridge, MA

Average rainfall days in December - Cambridge, MA
  • Average rainfall days in December: 5.6 days

The month with the highest number of rainy days is July (9.6 days).
The month with the least rainy days is January (4.3 days).

Average snowfall in December
Cambridge, MA

Average snowfall in December - Cambridge, MA
  • Average snowfall in December: 0.71"

The month with the highest snowfall is December (0.71").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in December
Cambridge, MA

Average snowfall days in December - Cambridge, MA
  • Average snowfall days in December: 2.7 days

The month with the highest number of snowfall days is January (4.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

Average daylight in December /
Average sunshine in December
Cambridge, MA

Average daylight in December / Average sunshine in December - Cambridge, MA
  • Average daylight in December: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in December: 4h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in December
Cambridge, MA

Average sunshine days in December - Cambridge, MA
  • Average sunshine days in December: 23 days

The month with the most sunshine days is January (23.5 days).
The month with the least sunshine days is June (17.4 days).

Average UV index in December
Cambridge, MA

Average UV index in December - Cambridge, MA
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in December
Cambridge, MA

Average cloud cover in December - Cambridge, MA
  • Average cloud cover in December: 47

The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 32).

Average visibility in December
Cambridge, MA

Average visibility in December - Cambridge, MA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Cambridge, Massachusetts, USA

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