December weather forecast
Rock Glen, PA

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Weather in December

December, the first month of the winter in Rock Glen, is also a wintry month, with temperature in the range of an average low of 26.2°F (-3.2°C) and an average high of 37.2°F (2.9°C).

Temperature

During Rock Glen's transition into December, the average high-temperature lessens, moving from a frosty 46.9°F (8.3°C) in November to a cold 37.2°F (2.9°C). Rock Glen's nighttime temperature in December falls to an average of 26.2°F (-3.2°C).

Humidity

The average relative humidity in December is 83%.

Rainfall

In Rock Glen, in December, it is raining for 7.3 days, with typically 0.87" (22mm) of accumulated precipitation. In Rock Glen, during the entire year, the rain falls for 111.5 days and collects up to 11.34" (288mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Rock Glen, in December, during 5.3 snowfall days, 1.02" (26mm) of snow is typically accumulated. Throughout the year, there are 31.5 snowfall days, and 7.28" (185mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 18min of daylight.
On the first day of December, sunrise is at 7:10 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 7:29 am and sunset at 4:46 pm EST.

Sunshine

The average sunshine in December is 3.9h.

UV index

January through March, October through December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The daily high UV index of 2 in December translates into this advice:
While most individuals can withstand prolonged sun exposure, it is imperative that babies, children, and those with sensitive skin always be shielded. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Updated: Jul 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in December?

In Rock Glen, in December, the average high-temperature is 37.2°F (2.9°C), and the average low-temperature is 26.2°F (-3.2°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which combines relative humidity and air temperature, in July is estimated at 86°F (30°C).

What is the average humidity in December?

The average relative humidity in December is 83%.

How many days does it rain in December?

In Rock Glen, Pennsylvania, during December, the rain falls for 7.3 days and regularly aggregates up to 0.87" (22mm) of precipitation.

How many days does it snow in December?

In Rock Glen, during December, snow falls for 5.3 days and regularly aggregates up to 1.02" (26mm) of snow.

What is the month with the shortest days?

With an average of 9h and 18min of daylight, December has the shortest days of the year.

What is the average length of the day in December in Rock Glen?

The average day length in December is 9h and 17min.

What time are sunrise and sunset in December?

On the first day of December in Rock Glen, sunrise is at 7:10 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 7:29 am and sunset at 4:46 pm EST.

How many hours of sunshine does Rock Glen have in December?

In December, the average sunshine duration in Rock Glen is 3.9h.

What is the month with the lowest UV index?

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

What is the UV index reading in December in Rock Glen?

The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to Sun's UV rays.
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
Rock Glen, PA

Average temperature in December - Rock Glen, PA
  • Average high temperature in December: 37.2°F

The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (31.5°F).

  • Average low temperature in December: 26.2°F

The month with the highest average low temperature is July (59.5°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

Average pressure in December
Rock Glen, PA

Average pressure in December - Rock Glen, PA
  • Average pressure in December: 30.09"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
Rock Glen, PA

Average wind speed in December - Rock Glen, PA
  • Average wind speed in December: 7.8mph

The windiest month (with the highest average wind speed) is March (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).

Average humidity in December
Rock Glen, PA

Average humidity in December - Rock Glen, PA
  • Average humidity in December: 83%

The month with the highest relative humidity is February (84%).
The month with the lowest relative humidity is April (78%).

Average rainfall in December
Rock Glen, PA

Average rainfall in December - Rock Glen, PA
  • Average rainfall in December: 0.87"

The wettest month (with the highest rainfall) is May (1.26").
The driest month (with the least rainfall) is September (0.55").

Average rainfall days in December
Rock Glen, PA

Average rainfall days in December - Rock Glen, PA
  • Average rainfall days in December: 7.3 days

The month with the highest number of rainy days is May (13.8 days).
The month with the least rainy days is January (5.4 days).

Average snowfall in December
Rock Glen, PA

Average snowfall in December - Rock Glen, PA
  • Average snowfall in December: 1.02"

The month with the highest snowfall is February (1.81").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Rock Glen, PA

Average snowfall days in December - Rock Glen, PA
  • Average snowfall days in December: 5.3 days

The month with the highest number of snowfall days is January (9.9 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Rock Glen, PA

Average daylight in December / Average sunshine in December - Rock Glen, PA
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 3h and 5min

The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is February (Average sunshine: 3h and 36min).

Average sunshine days in December
Rock Glen, PA

Average sunshine days in December - Rock Glen, PA
  • Average sunshine days in December: 19 days

The month with the most sunshine days is November (20.6 days).
The month with the least sunshine days is May (14.3 days).

Average UV index in December
Rock Glen, PA

Average UV index in December - Rock Glen, PA
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average cloud cover in December
Rock Glen, PA

Average cloud cover in December - Rock Glen, PA
  • Average cloud cover in December: 60

The month with the most cloud cover is February (Cloud cover 61).
The month with the least cloud cover is July (Cloud cover 37).

Average visibility in December
Rock Glen, PA

Average visibility in December - Rock Glen, PA
  • Average visibility in December: 5mi

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

Rock Glen, Pennsylvania, USA

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