December weather forecast
Port Jefferson Station, NY

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Weather in December

The first month of the winter, December, is also a frosty month in Port Jefferson Station, New York, with an average temperature fluctuating between 43.7°F (6.5°C) and 36.5°F (2.5°C).

Temperature

Port Jefferson Station's December weather shows a modest shift in high-temperatures, falling from November's fresh 51.8°F (11°C) to a chilly 43.7°F (6.5°C). Port Jefferson Station's nocturnal December readings average at an icy 36.5°F (2.5°C), showing little variation from the daytime temperatures.

Humidity

In Port Jefferson Station, the average relative humidity in December is 73%.

Rainfall

December is the month with the most rainfall. Rain falls for 11.4 days and accumulates 3.58" (91mm) of precipitation.

Snowfall

January through March, October through December are months with snowfall. In Port Jefferson Station, in December, snow falls for 1.5 days, with typically accumulated 1.06" (27mm) of snow. In Port Jefferson Station, New York, during the entire year, snow falls for 12.6 days and aggregates up to 5.59" (142mm) of snow.

Daylight

The month with the shortest days is December, with an average of 9h and 18min of daylight.
On the first day of December, sunrise is at 6:58 am and sunset at 4:24 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:34 pm EST.

Sunshine

In December, the average sunshine 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 low threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: A maximum UV index of 2 in December translates into the following recommendations:
Children necessitate constant protection from sunlight, unlike the majority, who can remain under the sun for about an hour without burning. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Stay sun-safe with clothing that is both closely woven and worn loosely. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
Updated: Jun 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in December?

The high-temperature, in December, in Port Jefferson Station, records 43.7°F (6.5°C), while the low-temperature is 36.5°F (2.5°C).

What is the average humidity in December?

The average relative humidity in December is 73%.

What is the wettest month?

The month with the most rainfall is December, when the rain falls for 11.4 days and typically aggregates up to 3.58" (91mm) of precipitation.

How many days does it rain in December?

In Port Jefferson Station, during December, the rain falls for 11.4 days and regularly aggregates up to 3.58" (91mm) of precipitation.

How many days does it snow in December?

In December, it is snowing for 1.5 days. Throughout December, 1.06" (27mm) of snow is accumulated.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 18min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 17min.

When is the sunrise / sunset in December?

On the first day of December in Port Jefferson Station, sunrise is at 6:58 am and sunset at 4:24 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:34 pm EST.

How many hours of sunshine does Port Jefferson Station have in December?

In December, the average sunshine duration is 4.8h.

When is the lowest UV index?

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

How high is the UV index in December?

In Port Jefferson Station, the average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal hazard to health from unprotected exposure to UV radiation.
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
Port Jefferson Station, NY

Average temperature in December - Port Jefferson Station, NY
  • Average high temperature in December: 43.7°F

The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is January (37.6°F).

  • Average low temperature in December: 36.5°F

The months with the highest average low temperature are July and August (71.1°F).
The coldest month (with the lowest average low temperature) is January (29.1°F).

Average pressure in December
Port Jefferson Station, NY

Average pressure in December - Port Jefferson Station, NY
  • Average pressure in December: 30.06"Hg

The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Port Jefferson Station, NY

Average wind speed in December - Port Jefferson Station, NY
  • Average wind speed in December: 12.7mph

The windiest month (with the highest average wind speed) is January (12.9mph).
The calmest month (with the lowest average wind speed) is July (8.3mph).

Average humidity in December
Port Jefferson Station, NY

Average humidity in December - Port Jefferson Station, NY
  • Average humidity in December: 73%

The months with the highest relative humidity are May and June (77%).
The month with the lowest relative humidity is November (71%).

Average rainfall in December
Port Jefferson Station, NY

Average rainfall in December - Port Jefferson Station, NY
  • Average rainfall in December: 3.58"

The wettest month (with the highest rainfall) is December (3.58").
The driest month (with the least rainfall) is January (2.05").

Average rainfall days in December
Port Jefferson Station, NY

Average rainfall days in December - Port Jefferson Station, NY
  • Average rainfall days in December: 11.4 days

The month with the highest number of rainy days is July (16.5 days).
The month with the least rainy days is January (6.8 days).

Average snowfall in December
Port Jefferson Station, NY

Average snowfall in December - Port Jefferson Station, NY
  • Average snowfall in December: 1.06"

The month with the highest snowfall is March (2.13").
The months with the least snowfall are April, May, June, July, August and September (0").

Average snowfall days in December
Port Jefferson Station, NY

Average snowfall days in December - Port Jefferson Station, NY
  • Average snowfall days in December: 1.5 days

The month with the highest number of snowfall days is February (4.4 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Port Jefferson Station, NY

Average daylight in December / Average sunshine in December - Port Jefferson Station, NY
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 4h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in December
Port Jefferson Station, NY

Average sunshine days in December - Port Jefferson Station, NY
  • Average sunshine days in December: 17.6 days

The month with the most sunshine days is November (20.5 days).
The month with the least sunshine days is July (13 days).

Average UV index in December
Port Jefferson Station, NY

Average UV index in December - Port Jefferson Station, NY
  • 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
Port Jefferson Station, NY

Average cloud cover in December - Port Jefferson Station, NY
  • Average cloud cover in December: 49

The month with the most cloud cover is December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 28).

Average visibility in December
Port Jefferson Station, NY

Average visibility in December - Port Jefferson Station, NY
  • 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).

Port Jefferson Station, New York, USA

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