December weather forecast
Atglen, PA

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Weather in December

The first month of the winter, December, is still a cold month in Atglen, Pennsylvania, with an average temperature varying between 41.9°F (5.5°C) and 30.6°F (-0.8°C).

Temperature

The arrival of December corresponds with a temperature reduction, down from November's cool 50.9°F (10.5°C) to an icy 41.9°F (5.5°C). Atglen, during December nights, observes an average temperature of 30.6°F (-0.8°C).

Humidity

The average relative humidity in December is 80%.

Rainfall

In Atglen, in December, during 8.7 rainfall days, 1.54" (39mm) of precipitation is typically accumulated. Throughout the year, there are 138.3 rainfall days, and 19.76" (502mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, October through December. In Atglen, in December, snow falls for 2.7 days, with typically accumulated 1.14" (29mm) of snow. Throughout the year, there are 19.6 snowfall days, and 7.64" (194mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 24min of daylight.
On the first day of December, sunrise is at 7:07 am and sunset at 4:39 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 4:48 pm EST.

Sunshine

In December, the average sunshine is 4.7h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: An average maximum UV index of 2 in December leads to these recommendations:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.

Frequently asked questions

Is December cold?

In December, in Atglen, the average high-temperature is 41.9°F (5.5°C), and the average low-temperature is 30.6°F (-0.8°C). In August, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is estimated at 86°F (30°C).

What is the average humidity in December?

In Atglen, the average relative humidity in December is 80%.

How much does it rain in December?

In Atglen, during December, the rain falls for 8.7 days and regularly aggregates up to 1.54" (39mm) of precipitation.

How many days does it snow in December?

In December, it is snowing for 2.7 days. Throughout December, 1.14" (29mm) of snow is accumulated.

What is the month with the shortest days in Atglen?

The month with the shortest days is December, with an average of 9h and 24min of daylight.

How many hours of daylight does Atglen have in December?

In Atglen, the average day length in December is 9h and 23min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:07 am and sunset at 4:39 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 4:48 pm EST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.7h.

What is the month with the lowest UV index?

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2.

What is the UV index intensity in December?

In Atglen, the average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a low health risk 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
Atglen, PA

Average temperature in December - Atglen, PA
  • Average high temperature in December: 41.9°F

The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (35.6°F).

  • Average low temperature in December: 30.6°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

Average pressure in December
Atglen, PA

Average pressure in December - Atglen, PA
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in December
Atglen, PA

Average wind speed in December - Atglen, PA
  • Average wind speed in December: 8.3mph

The windiest months (with the highest average wind speed) are January, February and March (8.8mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).

Average humidity in December
Atglen, PA

Average humidity in December - Atglen, PA
  • Average humidity in December: 80%

The months with the highest relative humidity are May and October (81%).
The month with the lowest relative humidity is April (76%).

Average rainfall in December
Atglen, PA

Average rainfall in December - Atglen, PA
  • Average rainfall in December: 1.54"

The wettest month (with the highest rainfall) is August (2.72").
The driest month (with the least rainfall) is February (1.14").

Average rainfall days in December
Atglen, PA

Average rainfall days in December - Atglen, PA
  • Average rainfall days in December: 8.7 days

The month with the highest number of rainy days is July (16.8 days).
The month with the least rainy days is January (6.4 days).

Average snowfall in December
Atglen, PA

Average snowfall in December - Atglen, PA
  • Average snowfall in December: 1.14"

The month with the highest snowfall is March (2.32").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Atglen, PA

Average snowfall days in December - Atglen, PA
  • Average snowfall days in December: 2.7 days

The month with the highest number of snowfall days is January (5.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Atglen, PA

Average daylight in December / Average sunshine in December - Atglen, 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: 4h and 4min

The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).

Average sunshine days in December
Atglen, PA

Average sunshine days in December - Atglen, PA
  • Average sunshine days in December: 19.3 days

The month with the most sunshine days is November (20 days).
The month with the least sunshine days is July (12.4 days).

Average UV index in December
Atglen, PA

Average UV index in December - Atglen, PA
  • 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, March, November and December (UV index 2).

Average cloud cover in December
Atglen, PA

Average cloud cover in December - Atglen, PA
  • Average cloud cover in December: 49

The month with the most cloud cover is February (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 33).

Average visibility in December
Atglen, PA

Average visibility in December - Atglen, PA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).

Atglen, Pennsylvania, USA

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