December weather forecast
Westwood, MA

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Weather in December

December, the first month of the winter in Westwood, is also an icy month, with an average temperature fluctuating between 40.1°F (4.5°C) and 28.9°F (-1.7°C).

Temperature

Start of December brings a shift in the average high-temperature, falling from November's chilly 49.6°F (9.8°C) to a cold 40.1°F (4.5°C). During December, the average low-temperature is a subzero cold 28.9°F (-1.7°C).

Humidity

In Westwood, Massachusetts, the average relative humidity in December is 77%.

Rainfall

In December, the rain falls for 6.6 days. Throughout December, 0.67" (17mm) of precipitation is accumulated. Throughout the year, there are 97.1 rainfall days, and 7.13" (181mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, November and December. The months with the most snowfall are March and December, with an average 0.91" (23mm) of accumulated snow.

Daylight

The month with the shortest days is December, with an average of 9h and 12min of daylight.
On the first day of December, sunrise is at 6:54 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:22 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 estimate of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: The daily high UV index of 2 in December translates into this advice:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Be mindful! The reflection from snow can increase the Sun's UV radiation nearly twice.
Updated: Jul 11, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December in Westwood?

In Westwood, 40.1°F (4.5°C) is the average high-temperature and 28.9°F (-1.7°C) is the average low-temperature during December. In August, the average heat index (a.k.a. 'real feel', 'felt air temperature'), which represents the influence of relative humidity on air temperature, is estimated at 86°F (30°C).

What is the average humidity in December?

In December, the average relative humidity is 77%.

How much does it rain in December?

In Westwood, in December, it is raining for 6.6 days, with typically 0.67" (17mm) of accumulated precipitation.

When does it snow the most?

The months with the most snowfall are March and December, with an average 0.91" (23mm) of accumulated snow.

How many days does it snow in December?

In December, it is snowing for 3 days. Throughout December, 0.91" (23mm) of snow is accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 12min of daylight.

How many hours of daylight does Westwood have in December?

The average day length in December is 9h and 10min.

When are sunrise and sunset in December?

On the first day of December, sunrise is at 6:54 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:22 pm EST.

How many hours of sunshine does Westwood have in December?

The average sunshine duration in December is 4.9h.

What are the months with the lowest UV index in Westwood?

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?

The average daily maximum UV index in December in Westwood is 2. A UV Index value of 2, and less, symbolizes a low health threat from unprotected exposure to 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
Westwood, MA

Average temperature in December - Westwood, MA
  • Average high temperature in December: 40.1°F

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (34.3°F).

  • Average low temperature in December: 28.9°F

The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (22.3°F).

Average pressure in December
Westwood, MA

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

The month with the highest atmospheric pressure is November (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Westwood, MA

Average wind speed in December - Westwood, MA
  • Average wind speed in December: 8.4mph

The windiest months (with the highest average wind speed) are January, February and March (8.9mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).

Average humidity in December
Westwood, MA

Average humidity in December - Westwood, MA
  • Average humidity in December: 77%

The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (70%).

Average rainfall in December
Westwood, MA

Average rainfall in December - Westwood, MA
  • Average rainfall in December: 0.67"

The wettest month (with the highest rainfall) is April (0.79").
The driest month (with the least rainfall) is September (0.31").

Average rainfall days in December
Westwood, MA

Average rainfall days in December - Westwood, MA
  • Average rainfall days in December: 6.6 days

The month with the highest number of rainy days is July (11.7 days).
The month with the least rainy days is February (5.1 days).

Average snowfall in December
Westwood, MA

Average snowfall in December - Westwood, MA
  • Average snowfall in December: 0.91"

The months with the highest snowfall are March and December (0.91").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in December
Westwood, MA

Average snowfall days in December - Westwood, MA
  • Average snowfall days in December: 3 days

The month with the highest number of snowfall days is January (5 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
Westwood, MA

Average daylight in December / Average sunshine in December - Westwood, 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 12min).

  • 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
Westwood, MA

Average sunshine days in December - Westwood, MA
  • Average sunshine days in December: 21.1 days

The month with the most sunshine days is November (22 days).
The month with the least sunshine days is July (16.8 days).

Average UV index in December
Westwood, MA

Average UV index in December - Westwood, 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
Westwood, MA

Average cloud cover in December - Westwood, 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 33).

Average visibility in December
Westwood, MA

Average visibility in December - Westwood, 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).

Westwood, Massachusetts, USA

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