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
The transition to December results in a modest reduction in average high-temperature, moving from a fresh 52.3°F (11.3°C) in November to a frosty 44.1°F (6.7°C). Nights in December in West Sayville showcase an average temperature of 37.2°F (2.9°C), slightly cooler than the daytime.Humidity
The average relative humidity in December is 74%.Rainfall
December is the month with the most rainfall. Rain falls for 12.3 days and accumulates 3.74" (95mm) of precipitation.Snowfall
Months with snowfall are January through March, May, October and December. December is the first month it typically snows. Throughout December, in the average 2.4 snowfall days, it receives 1.22" (31mm) of snow. Throughout the year, there are 14.7 snowfall days, and 6.14" (156mm) of snow is accumulated.Ocean temperature
In West Sayville, the average seawater temperature in December is 48.9°F (9.4°C).Note: Swimming in 48.9°F (9.4°C) can be lethal. Merely spending a few minutes in 55.4°F (13°C) waters feels harsh, and venturing below 50°F (10°C) might disrupt breathing control and bring about cold shock, contingent on individual resilience.
Daylight
December has the shortest days of the year, with an average of 9h and 18min of daylight.On the first day of December, sunrise is at 6:57 am and sunset at 4:25 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:35 pm EST.
Sunshine
In December, the average sunshine in West Sayville is 4.9h.UV index
January through March and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: The UV index of 2 during December translates into the following guidance:
Most individuals face no significant issues with extended sun exposure, but it is always essential to protect children, babies, and those with sensitive skin. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Be attentive! The reflective property of snow can nearly double the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold during December?
What is the average humidity in December?
What is the rainiest month?
How much does it rain in December?
When does it start snowing?
What is the water temperature in December?
What is the month with the shortest days?
How many hours of daylight does West Sayville have in December?
What time are sunrise and sunset in December?
How many hours of sunshine does West Sayville have in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
West Sayville, NY
- Average high temperature in December: 44.1°F
The warmest month (with the highest average high temperature) is August (78.1°F).
The month with the lowest average high temperature is January (37.9°F).
- Average low temperature in December: 37.2°F
The month with the highest average low temperature is August (71.8°F).
The coldest month (with the lowest average low temperature) is January (30.2°F).
Average pressure in December
West Sayville, 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 Sayville, NY
- Average wind speed in December: 13.4mph
The windiest month (with the highest average wind speed) is January (13.8mph).
The calmest months (with the lowest average wind speed) are July and August (9mph).
Average humidity in December
West Sayville, NY
- Average humidity in December: 74%
The months with the highest relative humidity are May and June (78%).
The month with the lowest relative humidity is November (71%).
Average rainfall in December
West Sayville, NY
- Average rainfall in December: 3.74"
The wettest month (with the highest rainfall) is December (3.74").
The driest month (with the least rainfall) is January (2.17").
Average rainfall days in December
West Sayville, NY
- Average rainfall days in December: 12.3 days
The month with the highest number of rainy days is July (17.7 days).
The month with the least rainy days is January (8.3 days).
Average snowfall in December
West Sayville, NY
- Average snowfall in December: 1.22"
The month with the highest snowfall is March (2.13").
The months with the least snowfall are April, June, July, August, September and November (0").
Average snowfall days in December
West Sayville, NY
- Average snowfall days in December: 2.4 days
The month with the highest number of snowfall days is February (4.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in December
West Sayville, NY
- Average sea temperature in December: 49°F
The best month for swimming (with the highest average sea temperature) is August (74°F).
The coldest month (with the lowest average sea temperature) is February (39.7°F).
Average daylight in December /
Average sunshine in December
West Sayville, 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: 4h and 5min
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 Sayville, NY
- Average sunshine days in December: 16.9 days
The month with the most sunshine days is November (18.8 days).
The month with the least sunshine days is July (11.3 days).
Average UV index in December
West Sayville, 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 Sayville, 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 Sayville, 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 Sayville, New York, USA
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