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
December brings a decrease in the average high-temperature, falling from November's chilly 48.7°F (9.3°C) to a wintry 38.3°F (3.5°C). The mean low-temperature during December nights is a subzero cold 27.3°F (-2.6°C).Humidity
The average relative humidity in December in Grafton 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
January through May, November and December are months with snowfall in Grafton, Massachusetts. In December, in Grafton, it is snowing for 5 days. Throughout December, 3.03" (77mm) of snow is accumulated. In Grafton, during the entire year, snow falls for 32.5 days and aggregates up to 18.78" (477mm) of snow.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year in Grafton.On the first day of the month, sunrise is at 6:56 am and sunset at 4:15 pm. On the last day of December, 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 in Grafton, Massachusetts. A UV Index reading of 2, and below, represents a low health risk from exposure to the Sun's UV rays for ordinary individuals.Note: In December, the UV index of 2 transforms into the following advice:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Be attentive! The reflective property of snow can nearly double the Sun's UV radiation.
Frequently asked questions
How cold is it in Grafton in December?
What is the average humidity in December in Grafton?
What is the wettest month in Grafton?
How many days does it rain in December in Grafton?
How many days does it snow in December in Grafton?
What is the month with the shortest days in Grafton?
What is the average length of the day in December in Grafton?
When are sunrise and sunset in December in Grafton?
How long on average sun shines in December in Grafton?
What are the months with the lowest UV index in Grafton?
What is the UV index reading in December in Grafton?
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
Weather forecast for your location
2. Allow the app to use your location
