December weather forecast
West Islip, NY

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Weather in December

The first month of the winter, December, is also a frosty month in West Islip, New York, with temperature in the range of an average high of 44.1°F (6.7°C) and an average low of 36.9°F (2.7°C).

Temperature

A mild drop in West Islip's average high-temperature is observed in December, transitioning from a fresh 52.2°F (11.2°C) in November to a chilly 44.1°F (6.7°C). December notes an average low temperature of 36.9°F (2.7°C), subtly down from the daytime highs.

Humidity

The average relative humidity in December in West Islip, New York, is 74%.

Rainfall

In December, the rain falls for 12.3 days. Throughout December, 3.78" (96mm) of precipitation is accumulated. Throughout the year, there are 157 rainfall days, and 35.98" (914mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, October through December. In West Islip, in December, during 2.4 snowfall days, 1.34" (34mm) of snow is typically accumulated. Throughout the year, in West Islip, there are 14.4 snowfall days, and 6.06" (154mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 18min of daylight.
On the first day of the month, sunrise is at 6:58 am and sunset at 4:26 pm. On the last day of December, sunrise is at 7:17 am and sunset at 4:36 pm EST.

Sunshine

In West Islip, the average sunshine in December is 5h.

UV index

The months with the lowest UV index in West Islip are January through March and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the ordinary person.
Note: A maximum high UV index of 2 in December translates into the following recommendations:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. Direct Sun exposure should be minimized especially during midday when radiation is most intense. During bright days, sunglasses that offer UVA and UVB defense are recommended. Note well! The intensity of the Sun's UV rays can be nearly doubled by snow reflection.
Updated: Feb 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold does it get in West Islip in December?

In December, the average high-temperature and low-temperature in West Islip are 44.1°F (6.7°C) and 36.9°F (2.7°C) respectively.

What is the average humidity in December in West Islip?

In December, the average relative humidity in West Islip is 74%.

How much does it rain in West Islip in December?

In December, the rain falls for 12.3 days. Throughout December, 3.78" (96mm) of precipitation is accumulated.

How much does it snow in West Islip in December?

In West Islip, during December, snow falls for 2.4 days and regularly aggregates up to 1.34" (34mm) of snow.

What is the month with the shortest days in West Islip?

With an average of 9h and 18min of daylight, December has the shortest days of the year in West Islip, New York.

How many hours of daylight does West Islip have in December?

The average day length in December in West Islip is 9h and 19min.

When are sunrise and sunset in December in West Islip?

On the first day of December in West Islip, New York, sunrise is at 6:58 am and sunset at 4:26 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:36 pm EST.

How long on average sun shines in December in West Islip?

In December, the average sunshine duration in West Islip is 5h.

What are the months with the lowest UV index in West Islip?

The months with the lowest UV index in West Islip, New York, are January through March and December, with an average maximum UV index of 2.

What is the UV index reading in December in West Islip?

In December, the average daily maximum UV index is 2. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's 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
West Islip, NY

Average temperature in December - West Islip, NY
  • Average high temperature in December: 44.1°F

The warmest month (with the highest average high temperature) is July (79°F).
The month with the lowest average high temperature is January (37.9°F).

  • Average low temperature in December: 36.9°F

The months with the highest average low temperature are July and August (72°F).
The coldest month (with the lowest average low temperature) is January (30.4°F).

Average pressure in December
West Islip, NY

Average pressure in December - West Islip, 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
West Islip, NY

Average wind speed in December - West Islip, NY
  • Average wind speed in December: 13.1mph

The windiest month (with the highest average wind speed) is January (13.6mph).
The calmest month (with the lowest average wind speed) is July (8.9mph).

Average humidity in December
West Islip, NY

Average humidity in December - West Islip, NY
  • Average humidity in December: 74%

The month with the highest relative humidity is May (78%).
The month with the lowest relative humidity is November (71%).

Average rainfall in December
West Islip, NY

Average rainfall in December - West Islip, NY
  • Average rainfall in December: 3.78"

The wettest month (with the highest rainfall) is July (3.98").
The driest month (with the least rainfall) is January (2.2").

Average rainfall days in December
West Islip, NY

Average rainfall days in December - West Islip, NY
  • Average rainfall days in December: 12.3 days

The month with the highest number of rainy days is July (17.3 days).
The month with the least rainy days is January (8.1 days).

Average snowfall in December
West Islip, NY

Average snowfall in December - West Islip, NY
  • Average snowfall in December: 1.34"

The month with the highest snowfall is March (2.17").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
West Islip, NY

Average snowfall days in December - West Islip, NY
  • Average snowfall days in December: 2.4 days

The month with the highest number of snowfall days is February (4.2 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
West Islip, NY

Average daylight in December / Average sunshine in December - West Islip, NY
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 5h and 0min

The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).

Average sunshine days in December
West Islip, NY

Average sunshine days in December - West Islip, NY
  • Average sunshine days in December: 16.4 days

The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is July (11.4 days).

Average UV index in December
West Islip, NY

Average UV index in December - West Islip, 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 and December (UV index 2).

Average cloud cover in December
West Islip, NY

Average cloud cover in December - West Islip, NY
  • Average cloud cover in December: 48

The month with the most cloud cover is December (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 27).

Average visibility in December
West Islip, NY

Average visibility in December - West Islip, 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).

West Islip, New York, USA

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