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
December
Weather in December
Temperature
The average high-temperature decreases in December, shifting from a chilly 49.5°F (9.7°C) in November to an icy 39.9°F (4.4°C). The nights of December anticipate an average low-temperature of 29.7°F (-1.3°C).Humidity
In Boston, the average relative humidity in December is 76%.Rainfall
The months with the most rainfall are March, April and December, with an average 2.91" (74mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Boston, in December, during 5.2 snowfall days, 2.83" (72mm) of snow is typically accumulated. In Boston, during the entire year, snow falls for 29.8 days and aggregates up to 15.75" (400mm) of snow.Ocean temperature
In December, the average ocean temperature is 46.8°F (8.2°C).Note: Caution: 46.8°F (8.2°C) temperatures below 50°F (10°C) during swimming can result in intense cold shock and quickened breathing.
Daylight
December has the shortest days of the year, with an average of 9h and 6min of daylight.On the first day of the month, sunrise is at 6:54 am and sunset at 4:12 pm. On the last day of December, sunrise is at 7:13 am and sunset at 4:21 pm EST.
Sunshine
In December, the average sunshine 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 estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for the average person.Note: The maximum UV index, 2 during December, leads to the following recommendations:
While many people can endure lengthy sun exposure, it remains imperative to safeguard babies, children, and fair-skinned individuals. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is December cold?
What is the average humidity in December?
What is the rainiest month?
How much does it rain in December?
How many days does it snow in December?
What is the water temperature in December?
What is the month with the shortest days in Boston?
How many hours of daylight does Boston have in December?
When is the sunrise / sunset in December?
How long on average sun shines in December?
What is the month with the lowest UV index in Boston?
How high is the UV index in December?
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).