Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average sea temperature in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
December in Boston, Massachusetts, comes with a decrease in the average high-temperature, falling from a frosty 49.5°F in November to an icy 39.9°F. Boston records an average temperature drop to a subzero cold 29.7°F in December.Humidity
The average relative humidity in December in Boston is 76%.Rainfall
The wettest months in Boston are March, April and December, with an average 2.91" of rainfall.Snowfall
Months with snowfall in Boston are January through May, October through December. In Boston, in December, during 5.2 snowfall days, 2.83" of snow is typically accumulated. In Boston, during the entire year, snow falls for 29.8 days and aggregates up to 15.75" of snow.Ocean temperature
In Boston, Massachusetts, the average seawater temperature in December is 46.8°F.Note: It is life-risking to swim in 46.8°F. Briefly staying in 55.4°F waters feels unsettling, and temperatures below 50°F might result in cold shock and loss of breath control, hinging on personal endurance.
Daylight
The month with the shortest days in Boston is December, with an average of 9h and 6min of daylight.On the first day of December, sunrise is at 6:53 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:21 pm EST.
Sunshine
In Boston, the average sunshine in December is 4.7h.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 vulnerability from exposure to the Sun's UV rays for average individuals.Note: In December, the maximum UV index of 2 suggests these recommendations:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
FAQ
Is it cold in Boston during December?
What is the average humidity in December in Boston?
What is the rainiest month in Boston?
How much does it rain in Boston in December?
How much does it snow in Boston in December?
What is the water temperature in December in Boston?
What is the month with the shortest days in Boston?
What is the average length of the day in December in Boston?
When is the sunrise / sunset in December in Boston?
How many hours of sunshine does Boston have in December?
What are the months with the lowest UV index in Boston?
How high is the UV index in December in Boston?
Average temperature in December
Boston, MA
- Average high temperature in December: 39.9°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (34.2°F).
- Average low temperature in December: 29.7°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure in December
Boston, 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
Boston, MA
- Average wind speed in December: 9.4mph
The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in December
Boston, MA
- Average humidity in December: 76%
The month with the highest relative humidity is February (77%).
The month with the lowest relative humidity is April (69%).
Average rainfall in December
Boston, MA
- Average rainfall in December: 2.91"
The wettest months (with the highest rainfall) are March, April and December (2.91").
The driest month (with the least rainfall) is September (1.26").
Average rainfall days in December
Boston, MA
- Average rainfall days in December: 10.1 days
The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is January (7.9 days).
Average snowfall in December
Boston, MA
- Average snowfall in December: 2.83"
The month with the highest snowfall is February (4.72").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Boston, MA
- Average snowfall days in December: 5.2 days
The months with the highest number of snowfall days are January and February (7.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in December
Boston, MA
- Average sea temperature in December: 46.6°F
The best month for swimming (with the highest average sea temperature) is August (67.9°F).
The coldest month (with the lowest average sea temperature) is February (38.1°F).
Average daylight in December /
Average sunshine in December
Boston, 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 4min
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 36min).
Average sunshine days in December
Boston, MA
- Average sunshine days in December: 16.5 days
The month with the most sunshine days is September (17.7 days).
The month with the least sunshine days is April (13 days).
Average UV index in December
Boston, 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
Boston, MA
- Average cloud cover in December: 48
The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in December
Boston, 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).
Boston, Massachusetts, USA
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