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
With the onset of December, Chelsea experiences a modest temperature adjustment, with the average high-temperature receding from a frosty 49.5°F (9.7°C) in November to a cold 39.9°F (4.4°C). During the December nights, an average temperature of 29.7°F (-1.3°C) is observed in Chelsea.Humidity
The average relative humidity in December in Chelsea, Massachusetts, is 76%.Rainfall
The months with the most rainfall in Chelsea 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 Chelsea, in December, during 5.2 snowfall days, 2.83" (72mm) of snow is typically accumulated. Throughout the year, in Chelsea, there are 29.8 snowfall days, and 15.75" (400mm) of snow is accumulated.Ocean temperature
In December, the average ocean temperature in Chelsea is 46.8°F (8.2°C).Note: Dipping in 46.8°F (8.2°C) at temperatures less than 50°F (10°C) without proper gear can lead to pronounced cold shock and breathing difficulties.
Daylight
The month with the shortest days is December, 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, in Chelsea, sunrise is at 7:13 am and sunset at 4:21 pm EST.
Sunshine
In Chelsea, 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 unsafe exposure to UV radiation for the average person.Note: A maximum high UV index of 2 in December translates into the following recommendations:
It is important to always shield children, babies, and individuals with sensitive skin from prolonged exposure to the sun. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Take heed! The reflection of snow can intensify the Sun's UV radiation nearly double.
Frequently asked questions
How cold is December in Chelsea?
What is the average humidity in December in Chelsea?
What is the rainiest month in Chelsea?
How much does it rain in Chelsea in December?
How many days does it snow in December in Chelsea?
What is the ocean temperature in December in Chelsea?
What is the month with the shortest days in Chelsea?
What is the average length of the day in December in Chelsea?
When are sunrise and sunset in December in Chelsea?
How many hours of sunshine does Chelsea have in December?
What is the month with the lowest UV index in Chelsea?
What is the UV index intensity in December in Chelsea?
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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