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 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
As November transitions to December, the average high-temperature falls from a chilly 47.3°F (8.5°C) to a cold 37.4°F (3°C). Groton experiences a nighttime temperature average of 26.2°F (-3.2°C) during December.Humidity
In Groton, the average relative humidity in December is 78%.Rainfall
December is the month with the most rainfall. Rain falls for 9.7 days and accumulates 2.8" (71mm) of precipitation.Snowfall
January through May, October through December are months with snowfall in Groton. In December, in Groton, it is snowing for 5.3 days. Throughout December, 4.45" (113mm) of snow is accumulated. In Groton, Massachusetts, during the entire year, snow falls for 32.6 days and aggregates up to 22.99" (584mm) of snow.Daylight
With an average of 9h and 6min of daylight, December has the shortest days of the year in Groton.On the first day of December in Groton, sunrise is at 6:57 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:23 pm EST.
Sunshine
In December, the average sunshine is 4.9h.UV index
The months with the lowest UV index in Groton are January through March, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: A maximum daily UV index of 2 during December morphs into the following directions:
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. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Take heed! Reflection from the snow can almost amplify the Sun's UV radiation by double.
Frequently asked questions
How cold is December in Groton?
What is the average humidity in December in Groton?
What is the wettest month in Groton?
How much does it rain in Groton in December?
How much does it snow in Groton in December?
What is the month with the shortest days in Groton?
How many hours of daylight does Groton have in December?
When are sunrise and sunset in December in Groton?
How many hours of sunshine does Groton have in December?
When is the lowest UV index in Groton?
How high is the UV index in December in Groton?
Average temperature in December
Groton, MA
- Average high temperature in December: 37.4°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (31.3°F).
- Average low temperature in December: 26.2°F
The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is January (19.4°F).
Average pressure in December
Groton, 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
Groton, MA
- Average wind speed in December: 8mph
The windiest month (with the highest average wind speed) is January (8.4mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).
Average humidity in December
Groton, MA
- Average humidity in December: 78%
The month with the highest relative humidity is February (81%).
The month with the lowest relative humidity is April (71%).
Average rainfall in December
Groton, MA
- Average rainfall in December: 2.8"
The wettest month (with the highest rainfall) is December (2.8").
The driest month (with the least rainfall) is September (1.3").
Average rainfall days in December
Groton, MA
- Average rainfall days in December: 9.7 days
The month with the highest number of rainy days is May (15.5 days).
The month with the least rainy days is February (7.7 days).
Average snowfall in December
Groton, MA
- Average snowfall in December: 4.45"
The month with the highest snowfall is February (6.3").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Groton, MA
- Average snowfall days in December: 5.3 days
The month with the highest number of snowfall days is January (8.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Groton, MA
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in December: 4h and 5min
The month with the most sunshine is August (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in December
Groton, MA
- Average sunshine days in December: 17.7 days
The month with the most sunshine days is November (18.4 days).
The month with the least sunshine days is May (13.5 days).
Average UV index in December
Groton, 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
Groton, MA
- Average cloud cover in December: 47
The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 34).
Average visibility in December
Groton, MA
- Average visibility in December: 6mi
The months with the highest visibility are April, October, November and December (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August and September (5mi).
Groton, Massachusetts, USA
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