December weather forecastKeystone, WV
December
Weather in December
December, the first month of the winter in Keystone, is also a frosty month, with an average temperature ranging between max 44.4°F (6.9°C) and min 31.1°F (-0.5°C).Temperature
The beginning of December subtly marks a decrease in the average high-temperature, transitioning from a fresh 52.5°F (11.4°C) in November to a chilly 44.4°F (6.9°C). Keystone's temperature lowers to a mean of 31.1°F (-0.5°C) during the nights in December.Humidity
In Keystone, the average relative humidity in December is 81%.Rainfall
In Keystone, during December, the rain falls for 11.6 days and regularly aggregates up to 2.8" (71mm) of precipitation. In Keystone, during the entire year, the rain falls for 172.5 days and collects up to 29.41" (747mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. The month with the most snowfall is December, when snow falls for 7.8 days and typically aggregates up to 4.41" (112mm) of snow.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 7:22 am and sunset at 5:08 pm. On the last day of December, sunrise is at 7:40 am and sunset at 5:18 pm EST.
Sunshine
In December, the average sunshine is 4.7h.UV index
January, February and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: The daily maximum UV index of 2 in December interprets into the following advice:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Keystone, WV
- Average high temperature in December: 44.4°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (39.2°F).
- Average low temperature in December: 31.1°F
The month with the highest average low temperature is July (60.3°F).
The coldest month (with the lowest average low temperature) is January (25°F).
Average pressure in December
Keystone, WV
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is November (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.99"Hg).
Average wind speed in December
Keystone, WV
- Average wind speed in December: 6.5mph
The windiest month (with the highest average wind speed) is January (7.3mph).
The calmest month (with the lowest average wind speed) is August (4.2mph).
Average humidity in December
Keystone, WV
- Average humidity in December: 81%
The month with the highest relative humidity is February (82%).
The months with the lowest relative humidity are July, August and November (76%).
Average rainfall in December
Keystone, WV
- Average rainfall in December: 2.8"
The wettest month (with the highest rainfall) is May (3.19").
The driest month (with the least rainfall) is September (1.54").
Average rainfall days in December
Keystone, WV
- Average rainfall days in December: 11.6 days
The month with the highest number of rainy days is May (19.7 days).
The months with the least rainy days are January and November (10.1 days).
Average snowfall in December
Keystone, WV
- Average snowfall in December: 4.41"
The month with the highest snowfall is December (4.41").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Keystone, WV
- Average snowfall days in December: 7.8 days
The month with the highest number of snowfall days is January (10.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Keystone, WV
- Average daylight in December: 9h and 36min
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: 4h and 42min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in December
Keystone, WV
- Average sunshine days in December: 13.8 days
The month with the most sunshine days is November (17.9 days).
The month with the least sunshine days is May (9.2 days).
Average UV index in December
Keystone, WV
- Average UV index in December: 2
The months with the highest UV index are June and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in December
Keystone, WV
- Average cloud cover in December: 55
The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are June and August (Cloud cover 36).
Average visibility in December
Keystone, WV
- Average visibility in December: 5mi
The months with the highest visibility are April and November (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October and December (5mi).
