December weather forecast
Penn, PA

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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.
Updated: Jul 18, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is it cold in Penn during December?

The high-temperature, in December, in Penn, is 39°F (3.9°C), while the low-temperature averages to 27.7°F (-2.4°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines air temperature and relative humidity, in August is evaluated at 86°F (30°C).

What is the average humidity in December in Penn?

In Penn, the average relative humidity in December is 84%.

How many days does it rain in December?

In December, the rain falls for 13.1 days. Throughout December, 2.99" (76mm) of precipitation is accumulated.

How many days does it snow in December?

In Penn, in December, during 13.5 snowfall days, 5.75" (146mm) of snow is typically accumulated.

What is the month with the shortest days in Penn?

With an average of 9h and 24min of daylight, December has the shortest days of the year.

How many hours of daylight does Penn have in December?

In December, the average day length is 9h and 21min.

When is the sunrise / sunset in December?

In December, on the first day of the month, 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.

How long on average sun shines in December?

The average sunshine duration in December is 3.4h.

What is the month with the lowest UV index in Penn?

December is the month with the lowest UV index in Penn, with an average maximum UV index of 1.

What is the UV index intensity in December?

In December, the average daily maximum UV index is 1. A UV Index estimate of 2, and below, represents a low health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Penn, PA

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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 / Average sunshine in December - Penn, 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
Penn, PA

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 - 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 - 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 - 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).

Penn, Pennsylvania, USA

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