December weather forecast
Acton, MA

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Weather in December

December, the first month of the winter in Acton, is also an icy month, with an average temperature varying between 38.3°F (3.5°C) and 27.3°F (-2.6°C).

Temperature

December implies a gentle temperature shift, with average high-temperatures reducing from November's chilly 48.6°F (9.2°C) to a cold 38.3°F (3.5°C). Acton, during the nights of December, experiences an average temperature drop to a freezing cold 27.3°F (-2.6°C).

Humidity

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

Rainfall

In Acton, in December, during 7.5 rainfall days, 1.34" (34mm) of precipitation is typically accumulated. In Acton, Massachusetts, during the entire year, the rain falls for 116.3 days and collects up to 15.87" (403mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. In December, it is snowing for 4.2 days. Throughout December, 2.32" (59mm) of snow is accumulated. In Acton, during the entire year, snow falls for 25.5 days and aggregates up to 11.42" (290mm) of snow.

Daylight

With an average of 9h and 6min of daylight, December has the shortest days of the year in Acton, Massachusetts.
On the first day of the month, sunrise is at 6:56 am and sunset at 4:13 pm. On the last day of December, sunrise is at 7:15 am and sunset at 4:22 pm EST.

Sunshine

In December, the average sunshine is 4.8h.

UV index

The months with the lowest UV index in Acton, Massachusetts, 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 exposure to the Sun's UV radiation for ordinary individuals.
Note: The daily high UV index of 2 during December translates into the following recommendations:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
Updated: Jun 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold does it get in December?

The high-temperature, in December, in Acton, is 38.3°F (3.5°C), while the low-temperature averages to 27.3°F (-2.6°C). In August, the average heat index (a.k.a. 'feels like', 'real feel'), which calculates the temperature value influenced by the moisture in the air, is computed to be 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 Acton, in December, it is raining for 7.5 days, with typically 1.34" (34mm) of accumulated precipitation.

How many days does it snow in December?

In Acton, in December, snow falls for 4.2 days, with typically accumulated 2.32" (59mm) 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 Acton have in December?

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

What time are sunrise and sunset in December?

On the first day of December, sunrise is at 6:56 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:15 am and sunset at 4:22 pm EST.

How many hours of sunshine does Acton have in December?

In Acton, the average sunshine duration in December is 4.8h.

What are the months with 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.

What is the UV index reading in December?

The average daily maximum UV index in December 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
Acton, MA

Average temperature in December - Acton, MA
  • Average high temperature in December: 38.3°F

The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (32.5°F).

  • Average low temperature in December: 27.3°F

The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (20.1°F).

Average pressure in December
Acton, MA

Average pressure in December - Acton, 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 (29.92"Hg).

Average wind speed in December
Acton, MA

Average wind speed in December - Acton, MA
  • Average wind speed in December: 8.2mph

The windiest month (with the highest average wind speed) is January (8.6mph).
The calmest month (with the lowest average wind speed) is August (5.5mph).

Average humidity in December
Acton, MA

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

The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is April (70%).

Average rainfall in December
Acton, MA

Average rainfall in December - Acton, MA
  • Average rainfall in December: 1.34"

The wettest month (with the highest rainfall) is October (1.65").
The driest month (with the least rainfall) is September (0.79").

Average rainfall days in December
Acton, MA

Average rainfall days in December - Acton, MA
  • Average rainfall days in December: 7.5 days

The month with the highest number of rainy days is July (13.2 days).
The month with the least rainy days is February (5.4 days).

Average snowfall in December
Acton, MA

Average snowfall in December - Acton, MA
  • Average snowfall in December: 2.32"

The month with the highest snowfall is February (2.87").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Acton, MA

Average snowfall days in December - Acton, MA
  • Average snowfall days in December: 4.2 days

The month with the highest number of snowfall days is January (6.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Acton, 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 18min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).

Average sunshine days in December
Acton, MA

Average sunshine days in December - Acton, MA
  • Average sunshine days in December: 19.1 days

The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is April (15.8 days).

Average UV index in December
Acton, MA

Average UV index in December - Acton, 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
Acton, MA

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

The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 34).

Average visibility in December
Acton, MA

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

The months with the highest visibility are January, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is February (5mi).

Acton, Massachusetts, USA

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