December weather forecastMerrimack, NH
December
Weather in December
December marks the full arrival of winter in Merrimack with accompanying cold winds. The city is adorned with festive decorations, complementing the beauty of the snow-covered landscapes. A considered viewing reveals the city preparing to welcome the New Year, braving the icy grip of winter. Persistent winter weather conditions even lead to limited outdoor activities and events. During the peak of winter in December, the city witnesses maximum snowfall, reaching up to 2.99" (76mm).Temperature
The average high-temperature drops in December, from November's chilly 46.6°F (8.1°C) to a cold 36.3°F (2.4°C). An average low-temperature of 25.3°F (-3.7°C) is noted during the nights in December.Humidity
In December, the average relative humidity is 79%.Rainfall
In Merrimack, in December, it is raining for 6.3 days, with typically 1.1" (28mm) of accumulated precipitation. Throughout the year, in Merrimack, there are 104.4 rainfall days, and 12.95" (329mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, October through December. December is the month with the most snowfall. Snow falls for 4 days and accumulates 2.99" (76mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 6min of daylight.On the first day of December in Merrimack, sunrise is at 6:57 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:21 pm EST.
Sunshine
The average sunshine in December in Merrimack 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 minimal health vulnerability from unsafe exposure to UV radiation for average individuals.Note: In December, the maximum UV index of 2 suggests this advice:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection. 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
Merrimack, NH
- Average high temperature in December: 36.3°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 (30.6°F).
- Average low temperature in December: 25.3°F
The month with the highest average low temperature is July (61°F).
The coldest month (with the lowest average low temperature) is January (18°F).
Average pressure in December
Merrimack, NH
- 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
Merrimack, NH
- Average wind speed in December: 7.8mph
The windiest month (with the highest average wind speed) is January (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in December
Merrimack, NH
- Average humidity in December: 79%
The month with the highest relative humidity is February (81%).
The month with the lowest relative humidity is April (72%).
Average rainfall in December
Merrimack, NH
- Average rainfall in December: 1.1"
The wettest month (with the highest rainfall) is October (1.38").
The driest month (with the least rainfall) is January (0.75").
Average rainfall days in December
Merrimack, NH
- Average rainfall days in December: 6.3 days
The month with the highest number of rainy days is June (12.1 days).
The month with the least rainy days is January (4.1 days).
Average snowfall in December
Merrimack, NH
- Average snowfall in December: 2.99"
The month with the highest snowfall is December (2.99").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Merrimack, NH
- Average snowfall days in December: 4 days
The month with the highest number of snowfall days is January (7.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Merrimack, NH
- Average daylight in December: 9h and 6min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in December: 4h and 48min
The month with the most sunshine is August (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in December
Merrimack, NH
- Average sunshine days in December: 21.3 days
The months with the most sunshine days are January and December (21.3 days).
The month with the least sunshine days is June (16.7 days).
Average UV index in December
Merrimack, NH
- 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
Merrimack, NH
- Average cloud cover in December: 47
The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 33).
Average visibility in December
Merrimack, NH
- Average visibility in December: 6mi
The months with the highest visibility are January, April, November and December (6mi).
The months with the lowest visibility are February, March, May, June, July, August, September and October (5mi).
