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 corresponds with a reduction in the average high-temperature, down from November's chilly 49.3°F (9.6°C) to a cold 39.7°F (4.3°C). Castle Shannon, during December, witnesses an average low-temperature of 28.2°F (-2.1°C).Humidity
The average relative humidity in December in Castle Shannon, Pennsylvania, is 83%.Rainfall
In Castle Shannon, in December, during 10.7 rainfall days, 2.09" (53mm) of precipitation is typically accumulated. Throughout the year, there are 164 rainfall days, and 26.89" (683mm) of precipitation is accumulated.Snowfall
January through April, October through December are months with snowfall. In Castle Shannon, during December, snow falls for 11.8 days and regularly aggregates up to 2.64" (67mm) of snow. In Castle Shannon, Pennsylvania, during the entire year, snow falls for 53.3 days and aggregates up to 13.27" (337mm) of snow.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year in Castle Shannon, Pennsylvania.On the first day of the month, sunrise is at 7:24 am and sunset at 4:54 pm. On the last day of December, in Castle Shannon, sunrise is at 7:42 am and sunset at 5:03 pm EST.
Sunshine
In Castle Shannon, the average sunshine in December is 3.3h.UV index
The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for the average person.Note: In December, the maximum UV index of 1 transforms into these recommendations:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Always opt for UVA and UVB-resistant sunglasses on radiant days. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Frequently asked questions
How cold does it get in Castle Shannon in December?
What is the average humidity in December in Castle Shannon?
How much does it rain in Castle Shannon in December?
How much does it snow in Castle Shannon in December?
What is the month with the shortest days in Castle Shannon?
What is the average length of the day in December in Castle Shannon?
When is the sunrise / sunset in December in Castle Shannon?
How many hours of sunshine does Castle Shannon have in December?
When is the lowest UV index in Castle Shannon?
What is the UV index reading in December in Castle Shannon?
Average temperature in December
Castle Shannon, PA
- Average high temperature in December: 39.7°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (33.4°F).
- Average low temperature in December: 28.2°F
The month with the highest average low temperature is July (63°F).
The coldest month (with the lowest average low temperature) is January (20.8°F).
Average pressure in December
Castle Shannon, PA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in December
Castle Shannon, PA
- Average wind speed in December: 7.3mph
The windiest month (with the highest average wind speed) is January (7.9mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in December
Castle Shannon, PA
- Average humidity in December: 83%
The months with the highest relative humidity are January and February (84%).
The month with the lowest relative humidity is August (73%).
Average rainfall in December
Castle Shannon, PA
- Average rainfall in December: 2.09"
The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is November (1.61").
Average rainfall days in December
Castle Shannon, PA
- Average rainfall days in December: 10.7 days
The month with the highest number of rainy days is May (18.4 days).
The month with the least rainy days is January (8.5 days).
Average snowfall in December
Castle Shannon, PA
- Average snowfall in December: 2.64"
The month with the highest snowfall is January (3.46").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Castle Shannon, PA
- Average snowfall days in December: 11.8 days
The month with the highest number of snowfall days is January (16.3 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
Castle Shannon, PA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 3h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 2h and 54min).
Average sunshine days in December
Castle Shannon, PA
- Average sunshine days in December: 11 days
The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is February (9.5 days).
Average UV index in December
Castle Shannon, PA
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Castle Shannon, PA
- Average cloud cover in December: 66
The month with the most cloud cover is January (Cloud cover 69).
The month with the least cloud cover is August (Cloud cover 34).
Average visibility in December
Castle Shannon, PA
- Average visibility in December: 5mi
The months with the highest visibility are April, June, July, August and November (6mi).
The months with the lowest visibility are January, February, March, May, September, October and December (5mi).
Castle Shannon, Pennsylvania, USA
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