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 beginning of December brings a slight decrease in the average high-temperature, transitioning from a cool 53.4°F (11.9°C) in November to a frosty 45.3°F (7.4°C). During December, Glenallen's temperature falls to a steady low-temperature average of 32.9°F (0.5°C).Humidity
May, October and December, with an average relative humidity of 76%, are the most humid months in Glenallen.Rainfall
In Glenallen, in December, it is raining for 10.2 days, with typically 2.76" (70mm) of accumulated precipitation. Throughout the year, there are 160.9 rainfall days, and 32.99" (838mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, November and December. In Glenallen, during December, snow falls for 2.9 days and regularly aggregates up to 1.38" (35mm) of snow. Throughout the year, there are 17.1 snowfall days, and 10.2" (259mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 30min of daylight.On the first day of the month, sunrise is at 7:08 am and sunset at 4:46 pm. On the last day of December, sunrise is at 7:27 am and sunset at 4:55 pm EST.
Sunshine
The average sunshine in December in Glenallen, Maryland, is 5.1h.UV index
The months with the lowest UV index are January, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: The maximum UV index of 2 during December translates into these guidelines:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Take to heart! Snow reflection can almost magnify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average December temperature?
What are the most humid months?
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?
What is the average length of the day in December in Glenallen?
When is the sunrise / sunset in December?
How many hours of sunshine does Glenallen have in December?
When is the lowest UV index?
How high is the UV index in December?
Average temperature in December
Glenallen, MD
- Average high temperature in December: 45.3°F
The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (39°F).
- Average low temperature in December: 32.9°F
The month with the highest average low temperature is July (68.7°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).
Average pressure in December
Glenallen, MD
- Average pressure in December: 30.11"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
Glenallen, MD
- Average wind speed in December: 7.1mph
The windiest month (with the highest average wind speed) is March (8.1mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in December
Glenallen, MD
- Average humidity in December: 76%
The months with the highest relative humidity are May, October and December (76%).
The month with the lowest relative humidity is July (70%).
Average rainfall in December
Glenallen, MD
- Average rainfall in December: 2.76"
The wettest month (with the highest rainfall) is August (4.13").
The driest month (with the least rainfall) is January (2.17").
Average rainfall days in December
Glenallen, MD
- Average rainfall days in December: 10.2 days
The month with the highest number of rainy days is May (17.8 days).
The month with the least rainy days is November (8.8 days).
Average snowfall in December
Glenallen, MD
- Average snowfall in December: 1.38"
The months with the highest snowfall are January and March (3.03").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Glenallen, MD
- Average snowfall days in December: 2.9 days
The months with the highest number of snowfall days are January and February (5.1 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
Glenallen, MD
- Average daylight in December: 9h and 3min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 5h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).
Average sunshine days in December
Glenallen, MD
- Average sunshine days in December: 17.5 days
The month with the most sunshine days is November (19.4 days).
The months with the least sunshine days are May and July (11 days).
Average UV index in December
Glenallen, MD
- 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, November and December (UV index 2).
Average cloud cover in December
Glenallen, MD
- Average cloud cover in December: 45
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
Glenallen, MD
- 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).
Glenallen, Maryland, USA
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