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 transition into December subtly indicates a reduction in the average high-temperature, down to a frosty 47.3°F (8.5°C) from November's moderate 56.1°F (13.4°C). Herndon's temperature drops to an average low of 34.7°F (1.5°C) during the nights of December.Humidity
In December, the average relative humidity in Herndon is 78%.Rainfall
In Herndon, in December, it is raining for 12.4 days, with typically 3.5" (89mm) of accumulated precipitation. In Herndon, during the entire year, the rain falls for 179.3 days and collects up to 39.76" (1010mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In December, in Herndon, it is snowing for 3.1 days. Throughout December, 1.18" (30mm) of snow is accumulated. In Herndon, during the entire year, snow falls for 15.8 days and aggregates up to 5.35" (136mm) of snow.Daylight
December has the shortest days of the year in Herndon, Kentucky, with an average of 9h and 42min of daylight.On the first day of December in Herndon, sunrise is at 6:44 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:02 am and sunset at 4:44 pm CST.
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 in Herndon. A UV Index of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV rays for the average person.Note: The maximum UV index of 2 during December leads to these instructions:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Herndon in December?
What is the average humidity in December in Herndon?
How much does it rain in Herndon in December?
How much does it snow in Herndon in December?
What is the month with the shortest days in Herndon?
How many hours of daylight does Herndon have in December?
When is the sunrise / sunset in December in Herndon?
How many hours of sunshine does Herndon have in December?
What are the months with the lowest UV index in Herndon?
What is the UV index intensity in December in Herndon?
Average temperature in December
Herndon, KY
- Average high temperature in December: 47.3°F
The warmest month (with the highest average high temperature) is July (87.4°F).
The month with the lowest average high temperature is January (42.6°F).
- Average low temperature in December: 34.7°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (28.9°F).
Average pressure in December
Herndon, KY
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.96"Hg).
Average wind speed in December
Herndon, KY
- Average wind speed in December: 8.2mph
The windiest months (with the highest average wind speed) are February and April (8.8mph).
The calmest month (with the lowest average wind speed) is July (5.2mph).
Average humidity in December
Herndon, KY
- Average humidity in December: 78%
The months with the highest relative humidity are March and May (79%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Herndon, KY
- Average rainfall in December: 3.5"
The wettest month (with the highest rainfall) is February (4.06").
The driest month (with the least rainfall) is September (2.17").
Average rainfall days in December
Herndon, KY
- Average rainfall days in December: 12.4 days
The month with the highest number of rainy days is July (19.6 days).
The month with the least rainy days is November (10.8 days).
Average snowfall in December
Herndon, KY
- Average snowfall in December: 1.18"
The month with the highest snowfall is January (1.42").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Herndon, KY
- Average snowfall days in December: 3.1 days
The month with the highest number of snowfall days is January (4.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Herndon, KY
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in December: 4h and 4min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).
Average sunshine days in December
Herndon, KY
- Average sunshine days in December: 15.5 days
The months with the most sunshine days are October and November (17.8 days).
The month with the least sunshine days is July (8.6 days).
Average UV index in December
Herndon, KY
- 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 and December (UV index 2).
Average cloud cover in December
Herndon, KY
- Average cloud cover in December: 50
The month with the most cloud cover is February (Cloud cover 52).
The month with the least cloud cover is June (Cloud cover 29).
Average visibility in December
Herndon, KY
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Herndon, Kentucky, USA
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