December weather forecast
Somerville, MA

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Weather in December

December announces the arrival of winter in Somerville Massachusetts with an average high temperature of 39.6°F (4.2°C). It's a month of significant transformation as the city prepares to move from fall to the coldest season of the year. Snowfall reappears, covering the city in a white blanket towards the end of the year. Despite the cold weather, a festive atmosphere engulfs Somerville. Be prepared for the snow-capped Bostonian landscapes that highlight this season. The coldest month of the year finishes off punctuated by the merry moments of Christmas and New Year's celebrations.

Temperature

Somerville in December experiences a subtle temperature decline, with average high-temperatures reducing from a chilly 49.5°F (9.7°C) in November to a cold 39.6°F (4.2°C). Somerville, during December, witnesses an average low-temperature of 29.3°F (-1.5°C).

Humidity

The average relative humidity in December in Somerville is 76%.

Rainfall

In Somerville, in December, during 3.1 rainfall days, 0.43" (11mm) of precipitation is typically accumulated. In Somerville, during the entire year, the rain falls for 47.8 days and collects up to 4.13" (105mm) of precipitation.

Snowfall

Months with snowfall are January through May, November and December. The month with the most snowfall in Somerville is December, when snow falls for 2.4 days and typically aggregates up to 0.71" (18mm) of snow.

Daylight

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

Sunshine

In December, the average sunshine is 4.9h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 2 in December interprets into the following advice:
While most individuals can withstand prolonged sun exposure, it is imperative that babies, children, and those with sensitive skin always be shielded. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Take heed! Reflection from the snow can almost amplify the Sun's UV radiation by double.

Frequently asked questions

Is it cold during December?

The high-temperature, in December, in Somerville, is 39.6°F (4.2°C), while the low-temperature averages to 29.3°F (-1.5°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which factors the actual air temperature with the relative humidity, in July is calculated to be 86°F (30°C).

What is the average humidity in December?

The average relative humidity in December is 76%.

How many days does it rain in December?

In Somerville, in December, it is raining for 3.1 days, with typically 0.43" (11mm) of accumulated precipitation.

What is the snowiest month?

The month with the most snowfall is December, when snow falls for 2.4 days and typically aggregates up to 0.71" (18mm) of snow.

How much does it snow in Somerville in December?

In Somerville, in December, snow falls for 2.4 days, with typically accumulated 0.71" (18mm) of snow.

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.

What is the average length of the day in December?

In December, the average day length is 9h and 8min.

When is the sunrise / sunset in December?

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.

How long on average sun shines in December?

The average sunshine duration in December is 4.9h.

What is the month with the lowest UV index?

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

What is the UV index reading in December?

In Somerville, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low health threat from unsafe exposure to Sun's UV rays.
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
Somerville, MA

Average temperature in December - Somerville, 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 (64.8°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).

Average pressure in December
Somerville, MA

Average pressure in December - Somerville, 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
Somerville, MA

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

The windiest month (with the highest average wind speed) is January (9.6mph).
The calmest month (with the lowest average wind speed) is August (6mph).

Average humidity in December
Somerville, MA

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

The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (69%).

Average rainfall in December
Somerville, MA

Average rainfall in December - Somerville, MA
  • Average rainfall in December: 0.43"

The wettest month (with the highest rainfall) is November (0.55").
The driest month (with the least rainfall) is September (0.12").

Average rainfall days in December
Somerville, MA

Average rainfall days in December - Somerville, MA
  • Average rainfall days in December: 3.1 days

The month with the highest number of rainy days is April (5.9 days).
The months with the least rainy days are January and September (2.9 days).

Average snowfall in December
Somerville, MA

Average snowfall in December - Somerville, 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
Somerville, MA

Average snowfall days in December - Somerville, MA
  • Average snowfall days in December: 2.4 days

The month with the highest number of snowfall days is January (3.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Somerville, 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 36min).

Average sunshine days in December
Somerville, MA

Average sunshine days in December - Somerville, MA
  • Average sunshine days in December: 25.5 days

The month with the most sunshine days is December (25.5 days).
The month with the least sunshine days is July (22.8 days).

Average UV index in December
Somerville, MA

Average UV index in December - Somerville, 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
Somerville, MA

Average cloud cover in December - Somerville, 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
Somerville, MA

Average visibility in December - Somerville, 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).

Somerville, Massachusetts, USA

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