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 brings a decrease in the average high-temperature, shifting from a chilly 49.5°F (9.7°C) in November to a cold 39.9°F (4.4°C). In December, the average low-temperature records at a freezing cold 29.7°F (-1.3°C) during the nights.Humidity
In December, the average relative humidity is 76%.Rainfall
The wettest months are March, April and December, with an average 2.91" (74mm) of rainfall.Snowfall
Months with snowfall are January through May, October through December. In Chelsea, in December, snow falls for 5.2 days, with typically accumulated 2.83" (72mm) of snow. In Chelsea, during the entire year, snow falls for 29.8 days and aggregates up to 15.75" (400mm) of snow.Ocean temperature
In Chelsea, the average seawater temperature in December is 46.8°F (8.2°C).Note: With the appropriate swimsuit, one can swim in 46.8°F (8.2°C) even if temperatures dip below 50°F (10°C); otherwise, be ready for cold shock and breath issues. A fleeting swim around 55.4°F (13°C) is distressing.
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 6:54 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 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 reading of 2, and below, represents a low health risk from exposure to the Sun's UV rays for ordinary individuals.Note: A maximum daily UV index of 2 during December morphs into the following directions:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Be careful! The Sun's UV radiation can nearly be doubled by the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December?
What is the rainiest month in Chelsea?
How much does it rain in Chelsea in December?
How many days does it snow in December?
How cold is the water in December in Chelsea?
What is the month with the shortest days?
How many hours of daylight does Chelsea have in December?
When are sunrise and sunset in December?
How many hours of sunshine does Chelsea have in December?
What are the months with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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
Chelsea, 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).
Chelsea, Massachusetts, USA
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