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
The transition into December is accompanied by a temperature decrease, with the average high-temperature shifting from a chilly 49.5°F (9.7°C) in November to a wintry 39.6°F (4.2°C). Charlestown, during December nights, observes an average temperature of 29.3°F (-1.5°C).Humidity
In December, the average relative humidity in Charlestown is 76%.Rainfall
In Charlestown, during December, the rain falls for 3.1 days and regularly aggregates up to 0.43" (11mm) of precipitation. In Charlestown, during the entire year, the rain falls for 47.8 days and collects up to 4.13" (105mm) of precipitation.Snowfall
Months with snowfall are January through May, November and December. The month with the most snowfall is December, when snow falls for 2.4 days and typically aggregates up to 0.71" (18mm) of snow.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 4.9h.UV index
January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Charlestown, Massachusetts. A UV Index of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: In December, the maximum UV index of 2 translates into these guidelines:
In contrast to children, who must always be shielded from the sun, most people can tolerate up to an hour of sun exposure without any burns. To guard against the harmful effects of the Sun, minimize exposure during midday. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Be alert! Nearly double the UV rays from the Sun can be reflected by 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?
How many days does it rain in December?
What is the snowiest month?
How much does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Charlestown have in December?
When is the sunrise / sunset in December in Charlestown?
How many hours of sunshine does Charlestown have in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Charlestown, MA
- Average high temperature in December: 39.6°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (33.8°F).
- Average low temperature in December: 29.3°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in December
Charlestown, 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
Charlestown, MA
- Average wind speed in December: 9mph
The windiest month (with the highest average wind speed) is January (9.6mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity in December
Charlestown, MA
- Average humidity in December: 76%
The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (69%).
Average rainfall in December
Charlestown, MA
- Average rainfall in December: 0.43"
The wettest month (with the highest rainfall) is November (0.55").
The driest month (with the least rainfall) is September (0.12").
Average rainfall days in December
Charlestown, MA
- Average rainfall days in December: 3.1 days
The month with the highest number of rainy days is April (5.9 days).
The months with the least rainy days are January and September (2.9 days).
Average snowfall in December
Charlestown, MA
- Average snowfall in December: 0.71"
The month with the highest snowfall is December (0.71").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Charlestown, MA
- Average snowfall days in December: 2.4 days
The month with the highest number of snowfall days is January (3.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Charlestown, 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 5min
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
Charlestown, MA
- Average sunshine days in December: 25.5 days
The month with the most sunshine days is December (25.5 days).
The month with the least sunshine days is July (22.8 days).
Average UV index in December
Charlestown, 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
Charlestown, 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 32).
Average visibility in December
Charlestown, 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).
Charlestown, Massachusetts, USA
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