December weather forecast
Portsmouth, VA

Gold and brown trees and modern developed buildings in Downtown Portsmouth, Virginia
Gold and brown trees and modern developed buildings in Downtown Portsmouth, Virginia

Weather in December

December, the first month of the winter in Portsmouth, is also a fresh month, with an average temperature fluctuating between 51.4°F (10.8°C) and 40.5°F (4.7°C).

Temperature

In December, the average high-temperature slightly decreases from a mild 58.3°F (14.6°C) in November to a fresh 51.4°F (10.8°C). The average low-temperature, in Portsmouth, is 40.5°F (4.7°C).

Humidity

In December, the average relative humidity in Portsmouth is 77%.

Rainfall

In Portsmouth, during 10.8 rainfall days, 1.46" (37mm) of precipitation is typically accumulated. In Portsmouth, during the entire year, the rain falls for 151.9 days and collects up to 20.35" (517mm) of precipitation.

Snowfall

Months with snowfall are January through March, November and December. In Portsmouth, in December, during 0.9 snowfall days, 0.24" (6mm) of snow is typically accumulated. Throughout the year, there are 5.3 snowfall days, and 1.18" (30mm) of snow is accumulated.

Ocean temperature

In Portsmouth, Virginia, the average water temperature is 52.7°F (11.5°C).
Note: Swimming in 52.7°F (11.5°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

Daylight

December has the shortest days of the year in Portsmouth, with an average of 9h and 41min of daylight.
On the first day of the month, sunrise is at 6:59 am and sunset at 4:49 pm. On the last day of December, in Portsmouth, sunrise is at 7:17 am and sunset at 4:58 pm EST.

Sunshine

In December, the average sunshine is 5.5h.

UV index

In Portsmouth, the average daily maximum UV index in December is 3. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the ordinary person.
Note: In December, the average maximum UV index of 3 translate into the following recommendations:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in December in Portsmouth?

The average high-temperature, in December, is 51.4°F (10.8°C), while the average low-temperature is 40.5°F (4.7°C). in August, the average heat index (a.k.a. 'real feel', 'feels like'), which calculates the temperature value influenced by the moisture in the air, is evaluated at 93.2°F (34°C).

What is the average humidity in December in Portsmouth?

In Portsmouth, Virginia, the average relative humidity in December is 77%.

How many days does it rain in December in Portsmouth?

In Portsmouth, Virginia, in December, during 10.8 rainfall days, 1.46" (37mm) of precipitation is typically accumulated.

How much does it snow in Portsmouth in December?

In Portsmouth, Virginia, in December, during 0.9 snowfall days, 0.24" (6mm) of snow is typically accumulated.

What is the ocean temperature in December in Portsmouth?

In December, the average ocean temperature in Portsmouth is 52.7°F (11.5°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the month with the shortest days in Portsmouth?

With an average of 9h and 41min of daylight, December has the shortest days of the year in Portsmouth.

What is the average length of the day in December in Portsmouth?

The average day length in December in Portsmouth is 9h and 41min.

When is the sunrise / sunset in December in Portsmouth?

On the first day of December in Portsmouth, sunrise is at 6:59 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:58 pm EST.

How many hours of sunshine does Portsmouth have in December?

In December, the average sunshine duration is 5.5h.

How high is the UV index in December in Portsmouth?

The average daily maximum UV index in December in Portsmouth, Virginia, is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Portsmouth, VA

Average temperature in December - Portsmouth, VA
  • Average high temperature in December: 51.4°F

The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (45.9°F).

  • Average low temperature in December: 40.5°F

The month with the highest average low temperature is July (73.6°F).
The coldest month (with the lowest average low temperature) is January (34.7°F).

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Average pressure in December
Portsmouth, VA

Average pressure in December - Portsmouth, VA
  • Average pressure in December: 30.12"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.96"Hg).

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Average wind speed in December
Portsmouth, VA

Average wind speed in December - Portsmouth, VA
  • Average wind speed in December: 9.1mph

The windiest months (with the highest average wind speed) are March and April (10.5mph).
The calmest month (with the lowest average wind speed) is August (7.5mph).

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Average humidity in December
Portsmouth, VA

Average humidity in December - Portsmouth, VA
  • Average humidity in December: 77%

The month with the highest relative humidity is May (78%).
The months with the lowest relative humidity are July and November (74%).

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Average rainfall in December
Portsmouth, VA

Average rainfall in December - Portsmouth, VA
  • Average rainfall in December: 1.46"

The wettest month (with the highest rainfall) is August (2.52").
The driest month (with the least rainfall) is November (1.1").

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Average rainfall days in December
Portsmouth, VA

Average rainfall days in December - Portsmouth, VA
  • Average rainfall days in December: 10.8 days

The month with the highest number of rainy days is July (17.4 days).
The month with the least rainy days is November (8.3 days).

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Average snowfall in December
Portsmouth, VA

Average snowfall in December - Portsmouth, VA
  • Average snowfall in December: 0.24"

The month with the highest snowfall is January (0.47").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in December
Portsmouth, VA

Average snowfall days in December - Portsmouth, VA
  • Average snowfall days in December: 0.9 days

The month with the highest number of snowfall days is January (2.2 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average sea temperature in December
Portsmouth, VA

Average sea temperature in December - Portsmouth, VA
  • Average sea temperature in December: 52.7°F

The best month for swimming (with the highest average sea temperature) is August (80°F).
The coldest month (with the lowest average sea temperature) is February (44.5°F).

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Average daylight in December /
Average sunshine in December
Portsmouth, VA

Average daylight in December / Average sunshine in December - Portsmouth, VA
  • Average daylight in December: 9h and 41min

The month with the longest days is June (Average daylight: 14h and 39min).
The month with the shortest days is December (Average daylight: 9h and 41min).

  • Average sunshine in December: 5h and 30min

The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 24min).

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Average sunshine days in December
Portsmouth, VA

Average sunshine days in December - Portsmouth, VA
  • Average sunshine days in December: 19.1 days

The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is August (10.8 days).

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Average UV index in December
Portsmouth, VA

Average UV index in December - Portsmouth, VA
  • Average UV index in December: 3

The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is January (UV index 2).

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Average cloud cover in December
Portsmouth, VA

Average cloud cover in December - Portsmouth, VA
  • Average cloud cover in December: 41

The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 26).

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Average visibility in December
Portsmouth, VA

Average visibility in December - Portsmouth, VA
  • 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).

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