December weather forecastGrantham, NH
December
Weather in December
December, the first month of the winter in Grantham, is also a subzero cold month, with an average temperature varying between 31.6°F (-0.2°C) and 21°F (-6.1°C).Temperature
In December, the meteorological conditions alter, with the average high-temperature shifting from a cold 42.6°F (5.9°C) in November to a subzero cold 31.6°F (-0.2°C). Grantham, in December, witnesses an average low-temperature of 21°F (-6.1°C).Humidity
In December, the average relative humidity is 83%.Rainfall
In Grantham, in December, it is raining for 10.9 days, with typically 2.91" (74mm) of accumulated precipitation. In Grantham, during the entire year, the rain falls for 153.2 days and collects up to 29.92" (760mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Grantham, in December, during 12 snowfall days, 7.32" (186mm) of snow is typically accumulated. Throughout the year, in Grantham, there are 65.4 snowfall days, and 42.72" (1085mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 0min of daylight.On the first day of the month, sunrise is at 7:02 am and sunset at 4:13 pm. On the last day of December, sunrise is at 7:21 am and sunset at 4:22 pm EST.
Sunshine
In December, the average sunshine is 4.3h.UV index
The months with the lowest UV index in Grantham are February and December, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: The UV index of 1 in December translates into these instructions:
While many people can endure lengthy sun exposure, it remains imperative to safeguard babies, children, and fair-skinned individuals. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Heed this! Snow reflection can almost augment the UV radiation of the sun by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Grantham, NH
- Average high temperature in December: 31.6°F
The warmest month (with the highest average high temperature) is July (78.8°F).
The month with the lowest average high temperature is January (25.9°F).
- Average low temperature in December: 21°F
The month with the highest average low temperature is July (57.2°F).
The coldest month (with the lowest average low temperature) is January (13.3°F).
Average pressure in December
Grantham, NH
- 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 (29.91"Hg).
Average wind speed in December
Grantham, NH
- Average wind speed in December: 7.2mph
The windiest months (with the highest average wind speed) are January, February, March and April (7.6mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in December
Grantham, NH
- Average humidity in December: 83%
The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is April (75%).
Average rainfall in December
Grantham, NH
- Average rainfall in December: 2.91"
The wettest month (with the highest rainfall) is October (3.39").
The driest month (with the least rainfall) is September (2.05").
Average rainfall days in December
Grantham, NH
- Average rainfall days in December: 10.9 days
The month with the highest number of rainy days is June (16.8 days).
The month with the least rainy days is February (7.9 days).
Average snowfall in December
Grantham, NH
- Average snowfall in December: 7.32"
The month with the highest snowfall is February (11.18").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Grantham, NH
- Average snowfall days in December: 12 days
The month with the highest number of snowfall days is February (14.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Grantham, NH
- Average daylight in December: 9h and 0min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in December: 4h and 18min
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 0min).
Average sunshine days in December
Grantham, NH
- Average sunshine days in December: 13.4 days
The month with the most sunshine days is September (16.8 days).
The month with the least sunshine days is February (11.3 days).
Average UV index in December
Grantham, NH
- Average UV index in December: 1
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are February and December (UV index 1).
Average cloud cover in December
Grantham, NH
- Average cloud cover in December: 55
The month with the most cloud cover is February (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 36).
Average visibility in December
Grantham, NH
- Average visibility in December: 5mi
The months with the highest visibility are January, March, April, May, June, July, August, September, October, November and December (5mi).
The month with the lowest visibility is February (4mi).





