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 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 onset of December brings a small shift in high-temperatures, falling from a refreshing 56.7°F (13.7°C) in November to a chilly 49.1°F (9.5°C). Nighttime temperature dips to a mean of 34.9°F (1.6°C) during December.Humidity
The most humid month is December, with an average relative humidity of 78%.Rainfall
In Roslyn Hills, in December, during 10.1 rainfall days, 1.93" (49mm) of precipitation is typically accumulated. Throughout the year, there are 151.1 rainfall days, and 26.22" (666mm) of precipitation is accumulated.Snowfall
January through April, November and December are months with snowfall. In December, it is snowing for 1.5 days. Throughout December, 1.5" (38mm) of snow is accumulated. In Roslyn Hills, during the entire year, snow falls for 10.5 days and aggregates up to 6.42" (163mm) of snow.Daylight
With an average of 9h and 36min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:06 am and sunset at 4:52 pm. On the last day of December, sunrise is at 7:24 am and sunset at 5:02 pm EST.
Sunshine
The month with the least sunshine is December, with an average of 5.2h of sunshine.UV index
The months with the lowest UV index are January, February and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: The UV index of 2 in December translates into these instructions:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in December?
What is the most humid month?
What is the average humidity in December?
How much does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
What time are sunrise and sunset in December?
What is the month with the least sunshine?
How long on average sun shines in December?
When is the lowest UV index?
How high is the UV index in December in Roslyn Hills?
Average temperature in December
Roslyn Hills, VA
- Average high temperature in December: 49.1°F
The warmest month (with the highest average high temperature) is July (90.7°F).
The month with the lowest average high temperature is January (44.2°F).
- Average low temperature in December: 34.9°F
The month with the highest average low temperature is July (69.6°F).
The coldest month (with the lowest average low temperature) is January (29.5°F).
Average pressure in December
Roslyn Hills, VA
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in December
Roslyn Hills, VA
- Average wind speed in December: 6mph
The windiest month (with the highest average wind speed) is April (7.4mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in December
Roslyn Hills, VA
- Average humidity in December: 78%
The month with the highest relative humidity is December (78%).
The month with the lowest relative humidity is July (68%).
Average rainfall in December
Roslyn Hills, VA
- Average rainfall in December: 1.93"
The wettest month (with the highest rainfall) is August (2.72").
The driest month (with the least rainfall) is September (1.65").
Average rainfall days in December
Roslyn Hills, VA
- Average rainfall days in December: 10.1 days
The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is November (8.8 days).
Average snowfall in December
Roslyn Hills, VA
- Average snowfall in December: 1.5"
The month with the highest snowfall is February (1.77").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Roslyn Hills, VA
- Average snowfall days in December: 1.5 days
The month with the highest number of snowfall days is February (3.5 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Roslyn Hills, VA
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 5h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is December (Average sunshine: 5h and 12min).
Average sunshine days in December
Roslyn Hills, VA
- Average sunshine days in December: 19.2 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is May (11.9 days).
Average UV index in December
Roslyn Hills, VA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in December
Roslyn Hills, VA
- Average cloud cover in December: 44
The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in December
Roslyn Hills, VA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Roslyn Hills, Virginia, USA
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