December weather forecast
Williamstown, MA

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Weather in December

December, the first month of the winter in Williamstown, is also an icy month, with an average temperature fluctuating between 22.1°F (-5.5°C) and 32.7°F (0.4°C).

Temperature

Williamstown's weather in December involves a decrease in the average high-temperature, moving down from November's frosty 43.7°F (6.5°C) to a cold 32.7°F (0.4°C). In Williamstown, the nighttime temperature averages to a subzero cold 22.1°F (-5.5°C) during December.

Humidity

In Williamstown, Massachusetts, the average relative humidity in December is 85%.

Rainfall

In Williamstown, during December, the rain falls for 11.1 days and regularly aggregates up to 3.19" (81mm) of precipitation. In Williamstown, during the entire year, the rain falls for 167.1 days and collects up to 35.98" (914mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In December, it is snowing for 11.2 days. Throughout December, 6.93" (176mm) of snow is accumulated. Throughout the year, there are 66.1 snowfall days, and 39.09" (993mm) of snow is accumulated.

Daylight

With an average of 9h and 6min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:04 am and sunset at 4:20 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:29 pm EST.

Sunshine

The average sunshine in December is 3.8h.

UV index

The months with the lowest UV index are February and December, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to UV radiation for ordinary individuals.
Note: In December, the average maximum UV index of 1 translates into the following recommendations:
Most individuals can handle sun exposure for up to an hour without burning, but children must always be shielded from sun exposure. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.
Updated: Aug 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December?

December temperatures vary between a high-temperature of 32.7°F (0.4°C) and a low-temperature of 22.1°F (-5.5°C).

What is the average humidity in December?

In Williamstown, the average relative humidity in December is 85%.

How many days does it rain in December?

In Williamstown, Massachusetts, during December, the rain falls for 11.1 days and regularly aggregates up to 3.19" (81mm) of precipitation.

How many days does it snow in December?

In Williamstown, during December, snow falls for 11.2 days and regularly aggregates up to 6.93" (176mm) of snow.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 6min of daylight.

How many hours of daylight does Williamstown have in December?

The average day length in December is 9h and 6min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 4:20 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:29 pm EST.

How many hours of sunshine does Williamstown have in December?

In Williamstown, the average sunshine duration in December is 3.8h.

What are the months with the lowest UV index?

February and December, with an average maximum UV index of 1, are months with the lowest UV index in Williamstown.

What is the UV index reading in December?

In December, the average daily maximum UV index is 1. A UV Index reading of 2, and below, represents 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
Williamstown, MA

Average temperature in December - Williamstown, MA
  • Average high temperature in December: 32.7°F

The warmest month (with the highest average high temperature) is July (78.6°F).
The month with the lowest average high temperature is January (27°F).

  • Average low temperature in December: 22.1°F

The month with the highest average low temperature is July (57°F).
The coldest month (with the lowest average low temperature) is January (14.7°F).

Average pressure in December
Williamstown, MA

Average pressure in December - Williamstown, MA
  • Average pressure in December: 30.06"Hg

The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in December
Williamstown, MA

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

The windiest months (with the highest average wind speed) are January and February (8.8mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

Average humidity in December
Williamstown, MA

Average humidity in December - Williamstown, MA
  • Average humidity in December: 85%

The month with the highest relative humidity is February (86%).
The month with the lowest relative humidity is April (77%).

Average rainfall in December
Williamstown, MA

Average rainfall in December - Williamstown, MA
  • Average rainfall in December: 3.19"

The wettest month (with the highest rainfall) is October (3.62").
The driest month (with the least rainfall) is March (2.6").

Average rainfall days in December
Williamstown, MA

Average rainfall days in December - Williamstown, MA
  • Average rainfall days in December: 11.1 days

The month with the highest number of rainy days is July (17.8 days).
The month with the least rainy days is February (7.8 days).

Average snowfall in December
Williamstown, MA

Average snowfall in December - Williamstown, MA
  • Average snowfall in December: 6.93"

The month with the highest snowfall is February (10").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Williamstown, MA

Average snowfall days in December - Williamstown, MA
  • Average snowfall days in December: 11.2 days

The month with the highest number of snowfall days is February (15.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

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

The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in December: 3h and 5min

The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is February (Average sunshine: 3h and 24min).

Average sunshine days in December
Williamstown, MA

Average sunshine days in December - Williamstown, MA
  • Average sunshine days in December: 11.7 days

The month with the most sunshine days is September (14.3 days).
The month with the least sunshine days is February (9 days).

Average UV index in December
Williamstown, MA

Average UV index in December - Williamstown, MA
  • Average UV index in December: 1

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are February and December (UV index 1).

Average cloud cover in December
Williamstown, MA

Average cloud cover in December - Williamstown, MA
  • Average cloud cover in December: 60

The month with the most cloud cover is February (Cloud cover 64).
The months with the least cloud cover are July and August (Cloud cover 38).

Average visibility in December
Williamstown, MA

Average visibility in December - Williamstown, MA
  • Average visibility in December: 5mi

The months with the highest visibility are January, March, April, May, June, July, August, September, October, November and December (5mi).
The month with the lowest visibility is February (4mi).

Williamstown, Massachusetts, USA

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