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
With December's onset, the average high-temperature recedes from November's frosty 49.1°F (9.5°C) to a cold 39.2°F (4°C). Throughout December, an average nighttime temperature of 28.6°F (-1.9°C) is experienced.Humidity
The average relative humidity in December is 77%.Rainfall
In December, the rain falls for 6.6 days. Throughout December, 0.79" (20mm) of precipitation is accumulated. Throughout the year, there are 106.3 rainfall days, and 8.5" (216mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, November and December. December is the month with the most snowfall. Snow falls for 3.1 days and accumulates 1.14" (29mm) of snow.Daylight
The month with the shortest days in Waltham is December, with an average of 9h and 6min of daylight.On the first day of December, sunrise is at 6:55 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:14 am and sunset at 4:22 pm EST.
Sunshine
In Waltham, the average sunshine in December is 5h.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 value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: The daily high UV index of 2 during December translates into the following recommendations:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold during December?
What is the average humidity in December?
How much does it rain in December?
What is the snowiest month?
How many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
What time are sunrise and sunset in December?
How many hours of sunshine does Waltham have in December?
What is the month with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Waltham, MA
- Average high temperature in December: 39.2°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (33.3°F).
- Average low temperature in December: 28.6°F
The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).
Average pressure in December
Waltham, 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 (29.92"Hg).
Average wind speed in December
Waltham, MA
- Average wind speed in December: 8.5mph
The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).
Average humidity in December
Waltham, 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
Waltham, MA
- Average rainfall in December: 0.79"
The wettest months (with the highest rainfall) are April and November (0.87").
The driest month (with the least rainfall) is September (0.35").
Average rainfall days in December
Waltham, MA
- Average rainfall days in December: 6.6 days
The month with the highest number of rainy days is July (12.4 days).
The month with the least rainy days is January (5.3 days).
Average snowfall in December
Waltham, MA
- Average snowfall in December: 1.14"
The month with the highest snowfall is December (1.14").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Waltham, MA
- Average snowfall days in December: 3.1 days
The month with the highest number of snowfall days is February (5.4 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Waltham, 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: 5h and 0min
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
Waltham, MA
- Average sunshine days in December: 21.4 days
The month with the most sunshine days is January (22.2 days).
The month with the least sunshine days is June (15.8 days).
Average UV index in December
Waltham, 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
Waltham, MA
- Average cloud cover in December: 46
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
Waltham, 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).
Waltham, Massachusetts, USA
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