December weather forecastStony Brook, NY
December
Weather in December
The first month of the winter, December, is also a frosty month in Stony Brook, New York, with an average temperature ranging between min 36.5°F (2.5°C) and max 43.7°F (6.5°C).Temperature
December signals a slight drop in average high-temperature, sliding from November's cool 51.8°F (11°C) to a frosty 43.7°F (6.5°C). Nighttime temperature reflects an average dip to a cold 36.5°F (2.5°C) in December, subtly cooler than its daytime highs.Humidity
In Stony Brook, the average relative humidity in December is 73%.Rainfall
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.Snowfall
January through March, October through December are months with snowfall in Stony Brook. In Stony Brook, in December, during 1.5 snowfall days, 1.06" (27mm) of snow is typically accumulated. In Stony Brook, during the entire year, snow falls for 12.6 days and aggregates up to 5.59" (142mm) of snow.Ocean temperature
In Stony Brook, in December, the average water temperature is 48.9°F (9.4°C).Note: Swimming in 48.9°F (9.4°C) is deemed hazardous. Exposure to temperatures below 50°F (10°C) leads to immediate severe cold shock and hyperventilation.
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 4:25 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:34 pm EST.
Sunshine
In Stony Brook, the average sunshine in December 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 in Stony Brook. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for the average person.Note: In December, a daily UV index of 2 turns into the following recommendations:
Babies, children, and individuals with sensitive skin should always have protection against extended sun exposure. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Be mindful! The reflection from snow can increase the Sun's UV radiation nearly twice.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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 sea temperature in December
Stony Brook, 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
Stony Brook, NY
- Average daylight in December: 9h and 18min
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 48min
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
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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
Stony Brook, 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).
