December weather forecast
Alton, NH

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Weather in December

December marks the return of winter with falling temperatures and increasing snowfall in Alton. A stark contrast from November's weather, December welcomes a high occurrence of snowfall up to 7.01" (178mm) and sees an average high temperature as low as 31.8°F (-0.1°C). The unmistakable chill in the air ushers in a festive and serene atmosphere throughout the town. As daylight shrinks to 9 hours per day, Altoners experience some of the shortest days of the year. Bearing the elements of a classic, frosty winter, December closes the weather calendar on a truly festive note in Alton.

Temperature

Welcoming December, Alton observes a shift in the average high-temperature, falling from November's frosty 43.3°F (6.3°C) to a subzero cold 31.8°F (-0.1°C). Nighttime temperature experiences an average drop to 21.6°F (-5.8°C) in December.

Humidity

The average relative humidity in December is 82%.

Rainfall

In Alton, New Hampshire, during December, the rain falls for 10.4 days and regularly aggregates up to 2.91" (74mm) of precipitation. In Alton, during the entire year, the rain falls for 152 days and collects up to 29.09" (739mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Alton, in December, during 10.6 snowfall days, 7.01" (178mm) of snow is typically accumulated. Throughout the year, there are 58.3 snowfall days, and 38.98" (990mm) of snow is accumulated.

Daylight

December has the shortest days of the year in Alton, with an average of 9h and 0min of daylight.
On the first day of the month, sunrise is at 6:58 am and sunset at 4:09 pm. On the last day of December, in Alton, sunrise is at 7:17 am and sunset at 4:18 pm EST.

Sunshine

In December, the average sunshine is 4.6h.

UV index

The months with the lowest UV index are January through March, October through December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV rays for the average person.
Note: In December, the maximum UV index of 2 translates into these guidelines:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Be vigilant! The reflective nature of snow can increase the Sun's UV radiation nearly twofold.
Updated: Jun 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December?

In December, the average high-temperature and low-temperature are 31.8°F (-0.1°C) and 21.6°F (-5.8°C) respectively.

What is the average humidity in December?

In December, the average relative humidity is 82%.

How much does it rain in December?

In Alton, in December, during 10.4 rainfall days, 2.91" (74mm) of precipitation is typically accumulated.

How much does it snow in December?

In December, it is snowing for 10.6 days. Throughout December, 7.01" (178mm) of snow is accumulated.

What is the month with the shortest days?

With an average of 9h and 0min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

The average day length in December is 9h and 1min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 6:58 am and sunset at 4:09 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:18 pm EST.

How many hours of sunshine does Alton have in December?

In December, the average sunshine duration is 4.6h.

When is the lowest UV index?

The months with the lowest UV index are January through March, October through December, with an average maximum UV index of 2.

How high is the UV index in December?

In December, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Alton, NH

Average temperature in December - Alton, NH
  • Average high temperature in December: 31.8°F

The warmest month (with the highest average high temperature) is July (78.3°F).
The month with the lowest average high temperature is January (26.1°F).

  • Average low temperature in December: 21.6°F

The month with the highest average low temperature is July (57.6°F).
The coldest month (with the lowest average low temperature) is January (12.9°F).

Average pressure in December
Alton, NH

Average pressure in December - Alton, NH
  • Average pressure in December: 30.03"Hg

The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in December
Alton, NH

Average wind speed in December - Alton, NH
  • Average wind speed in December: 6.6mph

The windiest months (with the highest average wind speed) are January and February (7.1mph).
The calmest months (with the lowest average wind speed) are July and August (4.7mph).

Average humidity in December
Alton, NH

Average humidity in December - Alton, NH
  • Average humidity in December: 82%

The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is April (76%).

Average rainfall in December
Alton, NH

Average rainfall in December - Alton, NH
  • Average rainfall in December: 2.91"

The wettest month (with the highest rainfall) is October (3.19").
The driest month (with the least rainfall) is September (1.61").

Average rainfall days in December
Alton, NH

Average rainfall days in December - Alton, NH
  • Average rainfall days in December: 10.4 days

The month with the highest number of rainy days is April (15.8 days).
The month with the least rainy days is February (8.3 days).

Average snowfall in December
Alton, NH

Average snowfall in December - Alton, NH
  • Average snowfall in December: 7.01"

The month with the highest snowfall is February (9.84").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Alton, NH

Average snowfall days in December - Alton, NH
  • Average snowfall days in December: 10.6 days

The month with the highest number of snowfall days is January (13.2 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Alton, NH

Average daylight in December / Average sunshine in December - Alton, 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 4min

The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).

Average sunshine days in December
Alton, NH

Average sunshine days in December - Alton, NH
  • Average sunshine days in December: 13.9 days

The month with the most sunshine days is September (16.9 days).
The month with the least sunshine days is April (11.4 days).

Average UV index in December
Alton, NH

Average UV index in December - Alton, NH
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average cloud cover in December
Alton, NH

Average cloud cover in December - Alton, NH
  • Average cloud cover in December: 50

The month with the most cloud cover is March (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 35).

Average visibility in December
Alton, NH

Average visibility in December - Alton, NH
  • Average visibility in December: 5mi

The months with the highest visibility are January, March, April, May, June, July, August, October, November and December (5mi).
The months with the lowest visibility are February and September (4mi).

Alton, New Hampshire, USA

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