December weather forecast
South Lancaster, MA

Share

Weather in December

The first month of the winter, December, is also a wintry month in South Lancaster, Massachusetts, with an average temperature varying between 37.4°F (3°C) and 26.6°F (-3°C).

Temperature

A subtle decrease in the average high-temperature marks December, falling from November's chilly 47.3°F (8.5°C) to a cold 37.4°F (3°C). The average low-temperature of 26.6°F (-3°C) is witnessed during December.

Humidity

In December, the average relative humidity in South Lancaster is 78%.

Rainfall

The month with the most rainfall in South Lancaster is December, when the rain falls for 10.7 days and typically aggregates up to 2.91" (74mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. In South Lancaster, during December, snow falls for 5.6 days and regularly aggregates up to 4.33" (110mm) of snow. In South Lancaster, during the entire year, snow falls for 36.5 days and aggregates up to 23.82" (605mm) 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 6:57 am and sunset at 4:14 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:24 pm EST.

Sunshine

In South Lancaster, the average sunshine in December is 4.8h.

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 of 2, and less, symbolizes a minimal health hazard from unsafe exposure to UV radiation for average individuals.
Note: In December, a regular UV index of 2 translates into these guidelines:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. Minimize direct exposure to the Sun during midday when its radiation is at its peak. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Attention! Nearly twice the Sun's UV radiation can be reflected by snow.
Updated: Aug 20, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December?

In South Lancaster, 37.4°F (3°C) is the average high-temperature and 26.6°F (-3°C) is the average low-temperature during December. The average heat index (a.k.a. 'felt air temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in July is calculated to be 87.8°F (31°C).

What is the average humidity in December?

In South Lancaster, the average relative humidity in December is 78%.

What is the wettest month?

December is the month with the most rainfall. Rain falls for 10.7 days and accumulates 2.91" (74mm) of precipitation.

How much does it rain in December?

In South Lancaster, Massachusetts, during December, the rain falls for 10.7 days and regularly aggregates up to 2.91" (74mm) of precipitation.

How many days does it snow in December in South Lancaster?

In South Lancaster, in December, during 5.6 snowfall days, 4.33" (110mm) of snow is typically accumulated.

What is the month with the shortest days?

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

How many hours of daylight does South Lancaster have in December?

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

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 6:57 am and sunset at 4:14 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:24 pm EST.

How long on average sun shines in December?

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.

How high is the UV index in December?

The average daily maximum UV index in December in South Lancaster is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability 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
South Lancaster, MA

Average temperature in December - South Lancaster, MA
  • Average high temperature in December: 37.4°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 (31.5°F).

  • Average low temperature in December: 26.6°F

The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is January (19.8°F).

Average pressure in December
South Lancaster, MA

Average pressure in December - South Lancaster, MA
  • Average pressure in December: 30.04"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
South Lancaster, MA

Average wind speed in December - South Lancaster, 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
South Lancaster, MA

Average humidity in December - South Lancaster, MA
  • Average humidity in December: 78%

The month with the highest relative humidity is February (81%).
The month with the lowest relative humidity is April (71%).

Average rainfall in December
South Lancaster, MA

Average rainfall in December - South Lancaster, MA
  • Average rainfall in December: 2.91"

The wettest month (with the highest rainfall) is December (2.91").
The driest month (with the least rainfall) is September (1.57").

Average rainfall days in December
South Lancaster, MA

Average rainfall days in December - South Lancaster, MA
  • Average rainfall days in December: 10.7 days

The month with the highest number of rainy days is July (16 days).
The month with the least rainy days is February (7.3 days).

Average snowfall in December
South Lancaster, MA

Average snowfall in December - South Lancaster, MA
  • Average snowfall in December: 4.33"

The month with the highest snowfall is February (6.1").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
South Lancaster, MA

Average snowfall days in December - South Lancaster, MA
  • Average snowfall days in December: 5.6 days

The month with the highest number of snowfall days is February (9.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
South Lancaster, MA

Average daylight in December / Average sunshine in December - South Lancaster, 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 12min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in December
South Lancaster, MA

Average sunshine days in December - South Lancaster, MA
  • Average sunshine days in December: 16.5 days

The month with the most sunshine days is November (17.4 days).
The month with the least sunshine days is July (12.8 days).

Average UV index in December
South Lancaster, MA

Average UV index in December - South Lancaster, 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
South Lancaster, MA

Average cloud cover in December - South Lancaster, 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 34).

Average visibility in December
South Lancaster, MA

Average visibility in December - South Lancaster, MA
  • Average visibility in December: 6mi

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

South Lancaster, Massachusetts, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location