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 onset of December results in a decrease in the average high-temperature, receding from a chilly 49.3°F (9.6°C) in November to a wintry 39.6°F (4.2°C). In the month of December, Mattapan's average low-temperature falls to a subzero cold 29.1°F (-1.6°C).Humidity
In Mattapan, the average relative humidity in December is 77%.Rainfall
The month with the most rainfall is December, when the rain falls for 10.7 days and typically aggregates up to 2.95" (75mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In December, it is snowing for 5.8 days. Throughout December, 4.21" (107mm) of snow is accumulated. Throughout the year, in Mattapan, there are 32.7 snowfall days, and 22.01" (559mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 6:54 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:22 pm EST.
Sunshine
In Mattapan, the average sunshine in December 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 Mattapan. A UV Index of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation for the average person.Note: In December, the maximum UV index of 2 suggests this advice:
Prolonged exposure to sunlight rarely troubles the majority, but constant protection is vital for babies, children, and fair-skinned people. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
What is the rainiest month?
How many days does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Mattapan have in December?
When is the sunrise / sunset in December in Mattapan?
How many hours of sunshine does Mattapan have in December?
When is the lowest UV index?
How high is the UV index in December?
Average temperature in December
Mattapan, MA
- Average high temperature in December: 39.6°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (33.6°F).
- Average low temperature in December: 29.1°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 (21.9°F).
Average pressure in December
Mattapan, MA
- Average pressure in December: 30.03"Hg
The month with the highest atmospheric pressure is November (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Mattapan, MA
- Average wind speed in December: 8.9mph
The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity in December
Mattapan, MA
- Average humidity in December: 77%
The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (70%).
Average rainfall in December
Mattapan, MA
- Average rainfall in December: 2.95"
The wettest month (with the highest rainfall) is December (2.95").
The driest month (with the least rainfall) is September (1.5").
Average rainfall days in December
Mattapan, MA
- Average rainfall days in December: 10.7 days
The month with the highest number of rainy days is July (15.8 days).
The months with the least rainy days are January and February (7.8 days).
Average snowfall in December
Mattapan, MA
- Average snowfall in December: 4.21"
The month with the highest snowfall is March (5.24").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Mattapan, MA
- Average snowfall days in December: 5.8 days
The month with the highest number of snowfall days is February (8.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Mattapan, 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 12min).
- 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 42min).
Average sunshine days in December
Mattapan, MA
- Average sunshine days in December: 16.5 days
The month with the most sunshine days is November (18 days).
The month with the least sunshine days is April (13.2 days).
Average UV index in December
Mattapan, 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
Mattapan, 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 33).
Average visibility in December
Mattapan, 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).
Mattapan, Massachusetts, USA
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