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 arrival of December signals a subtle shift in temperature, down from a cool 54.5°F (12.5°C) in November to a frosty 46.6°F (8.1°C). The month of December records an average low-temperature of 31.8°F (-0.1°C).Humidity
The months with the highest humidity are May, September, October and December, with an average relative humidity of 76%.Rainfall
In Rio, during December, the rain falls for 9.2 days and regularly aggregates up to 2.36" (60mm) of precipitation. In Rio, during the entire year, the rain falls for 155.9 days and collects up to 27.99" (711mm) of precipitation.Snowfall
January through April, November and December are months with snowfall. In December, in Rio, it is snowing for 1.9 days. Throughout December, 1.38" (35mm) of snow is accumulated. Throughout the year, there are 14.6 snowfall days, and 10.43" (265mm) of snow is accumulated.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 7:11 am and sunset at 4:54 pm. On the last day of December, sunrise is at 7:29 am and sunset at 5:04 pm EST.
Sunshine
January and December, with an average of 5.4h of sunshine, are months with the least sunshine.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV rays for the average person.Note: A maximum daily UV index of 2 during December morphs into the following directions:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are December temperatures?
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 in Rio?
What is the month with the least sunshine in Rio?
How long on average sun shines in December in Rio?
What are the months with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Rio, VA
- Average high temperature in December: 46.6°F
The warmest month (with the highest average high temperature) is July (88.2°F).
The month with the lowest average high temperature is January (41.5°F).
- Average low temperature in December: 31.8°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (26.1°F).
Average pressure in December
Rio, 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 (29.96"Hg).
Average wind speed in December
Rio, VA
- Average wind speed in December: 5.2mph
The windiest month (with the highest average wind speed) is April (6.3mph).
The calmest month (with the lowest average wind speed) is August (4.2mph).
Average humidity in December
Rio, VA
- Average humidity in December: 76%
The months with the highest relative humidity are May, September, October and December (76%).
The month with the lowest relative humidity is July (71%).
Average rainfall in December
Rio, VA
- Average rainfall in December: 2.36"
The wettest months (with the highest rainfall) are April and May (2.91").
The driest month (with the least rainfall) is January (1.69").
Average rainfall days in December
Rio, VA
- Average rainfall days in December: 9.2 days
The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is November (8.9 days).
Average snowfall in December
Rio, VA
- Average snowfall in December: 1.38"
The month with the highest snowfall is March (3.07").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Rio, VA
- Average snowfall days in December: 1.9 days
The month with the highest number of snowfall days is January (4.6 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
Rio, VA
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 5h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January and December (Average sunshine: 5h and 24min).
Average sunshine days in December
Rio, VA
- Average sunshine days in December: 19.9 days
The month with the most sunshine days is December (19.9 days).
The month with the least sunshine days is May (11.4 days).
Average UV index in December
Rio, VA
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Rio, VA
- Average cloud cover in December: 42
The month with the most cloud cover is March (Cloud cover 45).
The months with the least cloud cover are June and July (Cloud cover 31).
Average visibility in December
Rio, VA
- Average visibility in December: 5mi
The months with the highest visibility are February, March, April, June, July, August and November (6mi).
The months with the lowest visibility are January, May, September, October and December (5mi).
Rio, Virginia, USA
Weather forecast for your location
2. Allow the app to use your location