December weather forecastSouth Yarmouth, MA
December
Weather in December
The first month of the winter, December, is also a frosty month in South Yarmouth, Massachusetts, with an average temperature varying between 43.7°F (6.5°C) and 36.9°F (2.7°C).Temperature
Start of December brings a slight shift in the average high-temperature, dipping a bit from November's cool 51.3°F (10.7°C) to a chilly 43.7°F (6.5°C). In South Yarmouth, the December nights are characterized by an average low-temperature of 36.9°F (2.7°C), a minor dip from daytime readings.Humidity
The average relative humidity in December in South Yarmouth is 75%.Rainfall
In South Yarmouth, in December, it is raining for 10.8 days, with typically 1.38" (35mm) of accumulated precipitation. In South Yarmouth, during the entire year, the rain falls for 129 days and collects up to 14.21" (361mm) of precipitation.Snowfall
Months with snowfall are January through April and December. December is the first month it typically snows in South Yarmouth. Throughout December, in the average 4.5 snowfall days, it receives 0.39" (10mm) of snow. In South Yarmouth, during the entire year, snow falls for 20.8 days and aggregates up to 2.6" (66mm) of snow.Ocean temperature
In South Yarmouth, the average seawater temperature in December is 46°F (7.8°C).Note: Swimming in 46°F (7.8°C) is deemed hazardous. Exposure to temperatures below 50°F (10°C) leads to immediate severe cold shock and hyperventilation.
Daylight
December has the shortest days of the year in South Yarmouth, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 6:48 am and sunset at 4:11 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 4:20 pm EST.
Sunshine
The months with the least sunshine are February and December, with an average of 4.6h of sunshine.UV index
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for the average person.Note: An average maximum UV index of 2 in December leads to these recommendations:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
South Yarmouth, MA
- Average high temperature in December: 43.7°F
The warmest month (with the highest average high temperature) is August (72.1°F).
The month with the lowest average high temperature is January (38.5°F).
- Average low temperature in December: 36.9°F
The month with the highest average low temperature is August (68.5°F).
The coldest month (with the lowest average low temperature) is January (30.6°F).
Average pressure in December
South Yarmouth, 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
South Yarmouth, MA
- Average wind speed in December: 16.4mph
The windiest month (with the highest average wind speed) is January (16.8mph).
The calmest months (with the lowest average wind speed) are July and August (10.9mph).
Average humidity in December
South Yarmouth, MA
- Average humidity in December: 75%
The months with the highest relative humidity are June and July (84%).
The month with the lowest relative humidity is November (74%).
Average rainfall in December
South Yarmouth, MA
- Average rainfall in December: 1.38"
The wettest month (with the highest rainfall) is October (1.93").
The driest month (with the least rainfall) is August (0.94").
Average rainfall days in December
South Yarmouth, MA
- Average rainfall days in December: 10.8 days
The month with the highest number of rainy days is May (12.5 days).
The month with the least rainy days is February (8.3 days).
Average snowfall in December
South Yarmouth, MA
- Average snowfall in December: 0.39"
The month with the highest snowfall is January (0.87").
The months with the least snowfall are May, June, July, August, September, October and November (0").
Average snowfall days in December
South Yarmouth, MA
- Average snowfall days in December: 4.5 days
The month with the highest number of snowfall days is January (6.4 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in December
South Yarmouth, MA
- Average sea temperature in December: 46.1°F
The best month for swimming (with the highest average sea temperature) is August (67.5°F).
The coldest month (with the lowest average sea temperature) is March (39°F).
Average daylight in December /
Average sunshine in December
South Yarmouth, MA
- Average daylight in December: 9h and 12min
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 36min
The month with the most sunshine is August (Average sunshine: 10h and 48min).
The months with the least sunshine are February and December (Average sunshine: 4h and 36min).
Average sunshine days in December
South Yarmouth, MA
- Average sunshine days in December: 15.3 days
The month with the most sunshine days is September (18.6 days).
The month with the least sunshine days is February (14.3 days).
Average UV index in December
South Yarmouth, MA
- Average UV index in December: 2
The months with the highest UV index are 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 Yarmouth, MA
- Average cloud cover in December: 51
The month with the most cloud cover is December (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in December
South Yarmouth, 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).
