December weather forecastWellesley, MA
December
Weather in December
The first month of the winter, December, is still a cold month in Wellesley, Massachusetts, with an average temperature ranging between min 28.4°F (-2°C) and max 39°F (3.9°C).Temperature
In Wellesley, the beginning of December is marked by a lowered average high-temperature, shifting from November's chilly 49.1°F (9.5°C) to a wintry 39°F (3.9°C). During the month of December, the temperature falls to an average of 28.4°F (-2°C).Humidity
In Wellesley, the average relative humidity in December is 77%.Rainfall
In Wellesley, in December, it is raining for 9.6 days, with typically 2.36" (60mm) of accumulated precipitation. Throughout the year, there are 141.8 rainfall days, and 24.21" (615mm) of precipitation is accumulated.Snowfall
January through May, October through December are months with snowfall. In Wellesley, in December, during 5.3 snowfall days, 3.66" (93mm) of snow is typically accumulated. In Wellesley, during the entire year, snow falls for 28.5 days and aggregates up to 15.91" (404mm) of snow.Daylight
With an average of 9h and 6min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 6:55 am and sunset at 4:13 pm. On the last day of December, sunrise is at 7:14 am and sunset at 4:22 pm EST.
Sunshine
In December, the average sunshine is 5h.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 of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for average individuals.Note: The maximum UV index of 2 during December leads to these instructions:
Extended time in the sun generally does not harm most, but those with sensitive skin, infants, and children should always be protected. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Take heed! The reflection of snow can intensify the Sun's UV radiation nearly double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Wellesley, MA
- Average high temperature in December: 39°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 (33.1°F).
- Average low temperature in December: 28.4°F
The month with the highest average low temperature is July (63.5°F).
The coldest month (with the lowest average low temperature) is January (21.2°F).
Average pressure in December
Wellesley, 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
Wellesley, MA
- Average wind speed in December: 8.3mph
The windiest month (with the highest average wind speed) is January (8.8mph).
The calmest month (with the lowest average wind speed) is August (5.7mph).
Average humidity in December
Wellesley, 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
Wellesley, MA
- Average rainfall in December: 2.36"
The wettest month (with the highest rainfall) is March (2.4").
The driest month (with the least rainfall) is September (1.18").
Average rainfall days in December
Wellesley, MA
- Average rainfall days in December: 9.6 days
The month with the highest number of rainy days is July (15.6 days).
The month with the least rainy days is January (7.3 days).
Average snowfall in December
Wellesley, MA
- Average snowfall in December: 3.66"
The month with the highest snowfall is February (4.17").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Wellesley, MA
- Average snowfall days in December: 5.3 days
The month with the highest number of snowfall days is January (7.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Wellesley, MA
- Average daylight in December: 9h and 6min
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: 5h and 0min
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 48min).
Average sunshine days in December
Wellesley, MA
- Average sunshine days in December: 16.6 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is April (13.2 days).
Average UV index in December
Wellesley, 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
Wellesley, MA
- Average cloud cover in December: 46
The month with the most cloud cover is March (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in December
Wellesley, 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).
