December weather forecastPenn, PA
December
Weather in December
The first month of the winter, December, is also a wintry month in Penn, Pennsylvania, with an average temperature fluctuating between 27.7°F (-2.4°C) and 39°F (3.9°C).Temperature
With the beginning of December, the average high-temperature shows a decrease, transitioning from a chilly 48.9°F (9.4°C) in November to a cold 39°F (3.9°C). During December, Penn experiences an average low-temperature of 27.7°F (-2.4°C) at night.Humidity
In Penn, the average relative humidity in December is 84%.Rainfall
In Penn, in December, it is raining for 13.1 days, with typically 2.99" (76mm) of accumulated precipitation. Throughout the year, there are 183.8 rainfall days, and 35.16" (893mm) of precipitation is accumulated.Snowfall
January through May, October through December are months with snowfall. In Penn, in December, snow falls for 13.5 days, with typically accumulated 5.75" (146mm) of snow. In Penn, during the entire year, snow falls for 65 days and aggregates up to 28.98" (736mm) of snow.Daylight
The month with the shortest days in Penn is December, with an average of 9h and 24min of daylight.On the first day of December, sunrise is at 7:22 am and sunset at 4:52 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 5:02 pm EST.
Sunshine
In Penn, the average sunshine in December is 3.4h.UV index
December is the month with the lowest UV index, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for ordinary individuals.Note: The daily high UV index of 1 in December translates into this advice:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. During bright days, sunglasses that offer UVA and UVB defense are recommended. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Penn, PA
- Average high temperature in December: 39°F
The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in December: 27.7°F
The month with the highest average low temperature is July (61.2°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure in December
Penn, 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
Penn, PA
- Average wind speed in December: 7.8mph
The windiest month (with the highest average wind speed) is January (8.3mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in December
Penn, PA
- Average humidity in December: 84%
The months with the highest relative humidity are January and February (85%).
The months with the lowest relative humidity are April, July and August (77%).
Average rainfall in December
Penn, PA
- Average rainfall in December: 2.99"
The wettest month (with the highest rainfall) is May (3.78").
The driest month (with the least rainfall) is November (2.09").
Average rainfall days in December
Penn, PA
- Average rainfall days in December: 13.1 days
The month with the highest number of rainy days is May (20.1 days).
The month with the least rainy days is January (9.5 days).
Average snowfall in December
Penn, PA
- Average snowfall in December: 5.75"
The month with the highest snowfall is January (7.05").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Penn, PA
- Average snowfall days in December: 13.5 days
The month with the highest number of snowfall days is January (18.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Penn, PA
- Average daylight in December: 9h and 24min
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 24min
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
Penn, PA
- Average sunshine days in December: 9.1 days
The month with the most sunshine days is November (14 days).
The month with the least sunshine days is February (6.7 days).
Average UV index in December
Penn, 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
Penn, PA
- Average cloud cover in December: 65
The month with the most cloud cover is January (Cloud cover 70).
The month with the least cloud cover is August (Cloud cover 34).
Average visibility in December
Penn, PA
- Average visibility in December: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January and February (4mi).
