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
December marks a gentle change in average high-temperature, declining from November's refreshing 56.7°F (13.7°C) to a frosty 49.1°F (9.5°C). The nighttime temperature in Rockville, Virginia, dips to a cold 34.9°F (1.6°C) on average during December.Humidity
December is the most humid month, with an average relative humidity of 78%.Rainfall
In December, the rain falls for 10.1 days. Throughout December, 1.93" (49mm) of precipitation is accumulated. In Rockville, during the entire year, the rain falls for 151.1 days and collects up to 26.22" (666mm) of precipitation.Snowfall
Months with snowfall are January through April, November and December. In Rockville, Virginia, during December, snow falls for 1.5 days and regularly aggregates up to 1.5" (38mm) of snow. Throughout the year, there are 10.5 snowfall days, and 6.42" (163mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 7:07 am and sunset at 4:52 pm. On the last day of December, sunrise is at 7:25 am and sunset at 5:02 pm EST.
Sunshine
December has the least sunshine of the year, 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 low threat to health from unsafe exposure to UV radiation for the ordinary person.Note: In December, a regular UV index of 2 translates into these guidelines:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears. On your guard! Snow's reflection 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
What is the usual temperature for Rockville in December?
What is the most humid month?
What is the average humidity in December?
How much does it rain in December?
How much does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Rockville have in December?
When is the sunrise / sunset in December in Rockville?
What is the month with the least sunshine?
How long on average sun shines in December?
When is the lowest UV index?
What is the UV index intensity in December in Rockville?
Average temperature in December
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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
Rockville, 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).
Rockville, Virginia, USA
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