December weather forecast
Mechanics Valley, PA

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Weather in December

The first month of the winter, December, is also a wintry month in Mechanics Valley, Pennsylvania, with an average temperature ranging between min 30.9°F (-0.6°C) and max 41.9°F (5.5°C).

Temperature

December's onset brings a reduction in the average high-temperature, from a cool 51.4°F (10.8°C) in November to a wintry 41.9°F (5.5°C). In December, the average low-temperature records at a subzero cold 30.9°F (-0.6°C) during the nights.

Humidity

In Mechanics Valley, the average relative humidity in December is 78%.

Rainfall

In December, the rain falls for 10.9 days. Throughout December, 2.76" (70mm) of precipitation is accumulated. Throughout the year, there are 158.6 rainfall days, and 28.31" (719mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, October through December. In Mechanics Valley, in December, during 4.1 snowfall days, 2.13" (54mm) of snow is typically accumulated. In Mechanics Valley, Pennsylvania, during the entire year, snow falls for 24.6 days and aggregates up to 10.24" (260mm) of snow.

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 7:04 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:44 pm EST.

Sunshine

In December, the average sunshine is 5h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Mechanics Valley. A UV Index of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: In December, the average maximum UV index of 2 translates into the following recommendations:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December in Mechanics Valley?

In December, in Mechanics Valley, the average high-temperature is 41.9°F (5.5°C), and the average low-temperature is 30.9°F (-0.6°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which factors the actual air temperature with the relative humidity, in August is calculated to be 89.6°F (32°C).

What is the average humidity in December in Mechanics Valley?

The average relative humidity in December is 78%.

How many days does it rain in December?

In Mechanics Valley, during December, the rain falls for 10.9 days and regularly aggregates up to 2.76" (70mm) of precipitation.

How many days does it snow in December?

In Mechanics Valley, during December, snow falls for 4.1 days and regularly aggregates up to 2.13" (54mm) of snow.

What is the month with the shortest days?

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

How many hours of daylight does Mechanics Valley have in December?

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

What time are sunrise and sunset in December?

On the first day of December in Mechanics Valley, sunrise is at 7:04 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:44 pm EST.

How long on average sun shines in December?

In Mechanics Valley, the average sunshine duration in December is 5h.

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 December, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a minimal hazard to health from exposure to the Sun's 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
Mechanics Valley, PA

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

The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (35.6°F).

  • Average low temperature in December: 30.9°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

Average pressure in December
Mechanics Valley, PA

Average pressure in December - Mechanics Valley, PA
  • Average pressure in December: 30.09"Hg

The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in December
Mechanics Valley, PA

Average wind speed in December - Mechanics Valley, PA
  • Average wind speed in December: 7.6mph

The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).

Average humidity in December
Mechanics Valley, PA

Average humidity in December - Mechanics Valley, PA
  • Average humidity in December: 78%

The months with the highest relative humidity are February and October (79%).
The month with the lowest relative humidity is April (73%).

Average rainfall in December
Mechanics Valley, PA

Average rainfall in December - Mechanics Valley, PA
  • Average rainfall in December: 2.76"

The wettest month (with the highest rainfall) is July (2.87").
The driest month (with the least rainfall) is September (1.65").

Average rainfall days in December
Mechanics Valley, PA

Average rainfall days in December - Mechanics Valley, PA
  • Average rainfall days in December: 10.9 days

The month with the highest number of rainy days is July (17.3 days).
The month with the least rainy days is January (8.7 days).

Average snowfall in December
Mechanics Valley, PA

Average snowfall in December - Mechanics Valley, PA
  • Average snowfall in December: 2.13"

The month with the highest snowfall is March (2.76").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Mechanics Valley, PA

Average snowfall days in December - Mechanics Valley, PA
  • Average snowfall days in December: 4.1 days

The month with the highest number of snowfall days is January (7.9 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Mechanics Valley, PA

Average daylight in December / Average sunshine in December - Mechanics Valley, 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: 5h and 0min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in December
Mechanics Valley, PA

Average sunshine days in December - Mechanics Valley, PA
  • Average sunshine days in December: 16.6 days

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is June (11 days).

Average UV index in December
Mechanics Valley, PA

Average UV index in December - Mechanics Valley, 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
Mechanics Valley, PA

Average cloud cover in December - Mechanics Valley, PA
  • Average cloud cover in December: 48

The months with the most cloud cover are February and December (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 32).

Average visibility in December
Mechanics Valley, PA

Average visibility in December - Mechanics Valley, 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).

Mechanics Valley, Pennsylvania, USA

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