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 start of December signals a gentle decrease in the average high-temperature, transitioning from a cool 51.1°F (10.6°C) in November to an icy 42.4°F (5.8°C). Roslyn Harbor observes a slightly reduced average nighttime temperature of 34.7°F (1.5°C) during December.Humidity
February, May and December, with an average relative humidity of 75%, are the most humid months.Rainfall
December is the month with the most rainfall in Roslyn Harbor. Rain falls for 12.9 days and accumulates 4.06" (103mm) of precipitation.Snowfall
Months with snowfall are January through April, November and December. In Roslyn Harbor, in December, during 3.5 snowfall days, 1.54" (39mm) of snow is typically accumulated. In Roslyn Harbor, during the entire year, snow falls for 22.2 days and aggregates up to 7.24" (184mm) of snow.Ocean temperature
In Roslyn Harbor, New York, in December, the average water temperature is 48°F (8.9°C).Note: It is life-risking to swim in 48°F (8.9°C). Briefly staying in 55.4°F (13°C) waters feels unsettling, and temperatures below 50°F (10°C) might result in cold shock and loss of breath control, hinging on personal endurance.
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 7:00 am and sunset at 4:27 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 4:36 pm EST.
Sunshine
In Roslyn Harbor, New York, the average sunshine in December is 4.9h.UV index
The months with the lowest UV index in Roslyn Harbor are January through March, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health hazard from unsafe exposure to UV radiation for the average person.Note: In December, a daily maximum UV index of 2 leads to the following instructions:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. During bright days, sunglasses that offer UVA and UVB defense are recommended. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December in Roslyn Harbor?
What are the most humid months in Roslyn Harbor?
What is the average humidity in December in Roslyn Harbor?
What is the wettest month in Roslyn Harbor?
How many days does it rain in December in Roslyn Harbor?
How many days does it snow in December in Roslyn Harbor?
What is the ocean temperature in December in Roslyn Harbor?
What is the month with the shortest days in Roslyn Harbor?
What is the average length of the day in December in Roslyn Harbor?
When are sunrise and sunset in December in Roslyn Harbor?
How long on average sun shines in December in Roslyn Harbor?
What are the months with the lowest UV index in Roslyn Harbor?
What is the UV index reading in December in Roslyn Harbor?
Average temperature in December
Roslyn Harbor, NY
- Average high temperature in December: 42.4°F
The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (36.5°F).
- Average low temperature in December: 34.7°F
The months with the highest average low temperature are July and August (70.3°F).
The coldest month (with the lowest average low temperature) is January (27.3°F).
Average pressure in December
Roslyn Harbor, NY
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is November (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Roslyn Harbor, NY
- Average wind speed in December: 10.8mph
The windiest month (with the highest average wind speed) is January (11.2mph).
The calmest month (with the lowest average wind speed) is July (7.3mph).
Average humidity in December
Roslyn Harbor, NY
- Average humidity in December: 75%
The months with the highest relative humidity are February, May and December (75%).
The months with the lowest relative humidity are August and November (71%).
Average rainfall in December
Roslyn Harbor, NY
- Average rainfall in December: 4.06"
The wettest month (with the highest rainfall) is December (4.06").
The driest month (with the least rainfall) is September (2.4").
Average rainfall days in December
Roslyn Harbor, NY
- Average rainfall days in December: 12.9 days
The month with the highest number of rainy days is July (17.9 days).
The month with the least rainy days is January (9.3 days).
Average snowfall in December
Roslyn Harbor, NY
- Average snowfall in December: 1.54"
The month with the highest snowfall is March (2.01").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Roslyn Harbor, NY
- Average snowfall days in December: 3.5 days
The month with the highest number of snowfall days is January (6.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average sea temperature in December
Roslyn Harbor, NY
- Average sea temperature in December: 48.1°F
The best month for swimming (with the highest average sea temperature) is August (74.1°F).
The coldest month (with the lowest average sea temperature) is February (39.9°F).
Average daylight in December /
Average sunshine in December
Roslyn Harbor, 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 42min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in December
Roslyn Harbor, NY
- Average sunshine days in December: 15.5 days
The month with the most sunshine days is November (18 days).
The month with the least sunshine days is July (10.6 days).
Average UV index in December
Roslyn Harbor, 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
Roslyn Harbor, NY
- Average cloud cover in December: 47
The months with the most cloud cover are February and December (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 29).
Average visibility in December
Roslyn Harbor, 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).
Roslyn Harbor, New York, USA
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