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 December arrives, Grafton's weather displays a decrease in high-temperatures, transitioning from November's frosty 48.7°F (9.3°C) to a wintry 38.3°F (3.5°C). Grafton, in December, experiences an average temperature of 27.3°F (-2.6°C) at night.Humidity
In Grafton, the average relative humidity in December is 78%.Rainfall
December is the month with the most rainfall. Rain falls for 10.3 days and accumulates 3.15" (80mm) of precipitation.Snowfall
Months with snowfall are January through May, November and December. In Grafton, in December, during 5 snowfall days, 3.03" (77mm) of snow is typically accumulated. In Grafton, during the entire year, snow falls for 32.5 days and aggregates up to 18.78" (477mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 6:56 am and sunset at 4:15 pm. On the last day of the month, sunrise is at 7:15 am and sunset at 4:24 pm EST.
Sunshine
The average sunshine in December is 4.8h.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 low threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index, 2 in December, converts into the following recommendations:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost 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?
What is the average length of the day in December?
What time are sunrise and sunset in December?
How long on average sun shines in December?
When is the lowest UV index in Grafton?
What is the UV index reading in December?
Average temperature in December
Grafton, MA
- Average high temperature in December: 38.3°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 (32.5°F).
- Average low temperature in December: 27.3°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure in December
Grafton, 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 (29.93"Hg).
Average wind speed in December
Grafton, MA
- Average wind speed in December: 8.5mph
The windiest months (with the highest average wind speed) are January, February and March (8.9mph).
The calmest month (with the lowest average wind speed) is August (5.7mph).
Average humidity in December
Grafton, MA
- Average humidity in December: 78%
The month with the highest relative humidity is February (80%).
The month with the lowest relative humidity is April (71%).
Average rainfall in December
Grafton, MA
- Average rainfall in December: 3.15"
The wettest month (with the highest rainfall) is December (3.15").
The driest month (with the least rainfall) is September (1.54").
Average rainfall days in December
Grafton, MA
- Average rainfall days in December: 10.3 days
The month with the highest number of rainy days is July (16.8 days).
The month with the least rainy days is January (7.7 days).
Average snowfall in December
Grafton, MA
- Average snowfall in December: 3.03"
The month with the highest snowfall is March (4.92").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Grafton, MA
- Average snowfall days in December: 5 days
The month with the highest number of snowfall days is January (8.4 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
Grafton, 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 6min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in December
Grafton, 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 July (11.8 days).
Average UV index in December
Grafton, 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
Grafton, 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 36).
Average visibility in December
Grafton, MA
- Average visibility in December: 6mi
The months with the highest visibility are January, March, April, October, November and December (6mi).
The months with the lowest visibility are February, May, June, July, August and September (5mi).
Grafton, Massachusetts, USA
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