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 sea temperature 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
Portsmouth's progression into December involves a drop in the average high-temperature, receding from a frosty 47.1°F (8.4°C) in November to a cold 37.6°F (3.1°C). Portsmouth's nights in December experience an average temperature drop to a subzero cold 28°F (-2.2°C).Humidity
In December, the average relative humidity in Portsmouth is 78%.Rainfall
In Portsmouth, during December, the rain falls for 11.5 days and regularly aggregates up to 2.8" (71mm) of precipitation. Throughout the year, in Portsmouth, there are 144.2 rainfall days, and 27.48" (698mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, October through December. In Portsmouth, during December, snow falls for 7.5 days and regularly aggregates up to 3.9" (99mm) of snow. Throughout the year, there are 35.2 snowfall days, and 16.97" (431mm) of snow is accumulated.Ocean temperature
In Portsmouth, the average seawater temperature in December is 45.9°F (7.7°C).Note: If planning to swim in 45.9°F (7.7°C) under 50°F (10°C), wear a protective suit. Neglecting this advice might cause immediate cold shock and troubled breathing. A splash around 55.4°F (13°C) is not much warmer.
Daylight
December has the shortest days of the year in Portsmouth, with an average of 9h and 6min of daylight.On the first day of the month, sunrise is at 6:55 am and sunset at 4:09 pm. On the last day of December, sunrise is at 7:14 am and sunset at 4:18 pm EST.
Sunshine
February and December, with an average of 4.8h of sunshine, are months with the least sunshine in Portsmouth.UV index
January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Portsmouth. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for the ordinary person.Note: During December, 2 as the daily maximum UV index converts into the following advice:
Despite most people tolerating extended sun exposure, it is critical to always protect those with sensitive skin, infants, and children. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Frequently asked questions
Is December cold in Portsmouth?
What is the average humidity in December in Portsmouth?
How much does it rain in Portsmouth in December?
How much does it snow in Portsmouth in December?
What is the water temperature in December in Portsmouth?
What is the month with the shortest days in Portsmouth?
How many hours of daylight does Portsmouth have in December?
When is the sunrise / sunset in December in Portsmouth?
What is the month with the least sunshine in Portsmouth?
How many hours of sunshine does Portsmouth have in December?
When is the lowest UV index in Portsmouth?
How high is the UV index in December in Portsmouth?
Average temperature in December
Portsmouth, NH
- Average high temperature in December: 37.6°F
The warmest month (with the highest average high temperature) is July (76.3°F).
The month with the lowest average high temperature is January (31.8°F).
- Average low temperature in December: 28°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 (21.2°F).
Average pressure in December
Portsmouth, 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 (29.92"Hg).
Average wind speed in December
Portsmouth, NH
- Average wind speed in December: 10.8mph
The windiest month (with the highest average wind speed) is January (11.7mph).
The calmest month (with the lowest average wind speed) is July (6.6mph).
Average humidity in December
Portsmouth, NH
- Average humidity in December: 78%
The month with the highest relative humidity is June (80%).
The months with the lowest relative humidity are April and November (75%).
Average rainfall in December
Portsmouth, NH
- Average rainfall in December: 2.8"
The wettest month (with the highest rainfall) is October (2.83").
The driest month (with the least rainfall) is September (1.54").
Average rainfall days in December
Portsmouth, NH
- Average rainfall days in December: 11.5 days
The month with the highest number of rainy days is June (15 days).
The month with the least rainy days is January (7.5 days).
Average snowfall in December
Portsmouth, NH
- Average snowfall in December: 3.9"
The month with the highest snowfall is January (4.02").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Portsmouth, NH
- Average snowfall days in December: 7.5 days
The month with the highest number of snowfall days is January (8.8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in December
Portsmouth, NH
- Average sea temperature in December: 45.8°F
The best month for swimming (with the highest average sea temperature) is August (65.6°F).
The coldest month (with the lowest average sea temperature) is March (38.5°F).
Average daylight in December /
Average sunshine in December
Portsmouth, NH
- Average daylight in December: 9h and 1min
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 5min
The month with the most sunshine is August (Average sunshine: 10h and 36min).
The months with the least sunshine are February and December (Average sunshine: 4h and 48min).
Average sunshine days in December
Portsmouth, NH
- Average sunshine days in December: 14.5 days
The month with the most sunshine days is September (16.8 days).
The month with the least sunshine days is April (13.2 days).
Average UV index in December
Portsmouth, NH
- Average UV index in December: 2
The months with the highest UV index are 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
Portsmouth, NH
- 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 29).
Average visibility in December
Portsmouth, NH
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Portsmouth, New Hampshire, USA
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