Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
Mainland in December undergoes a mild reduction in the average high-temperature, shifting from November's cool 51.3°F (10.7°C) to an icy 42.1°F (5.6°C). Mainland, in December, observes a steady average low-temperature of 30.7°F (-0.7°C).Humidity
The months with the highest humidity are February, October and December, with an average relative humidity of 79%.Rainfall
In Mainland, in December, during 7.3 rainfall days, 1.02" (26mm) of precipitation is typically accumulated. Throughout the year, there are 116.6 rainfall days, and 10.63" (270mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, November and December. In Mainland, during December, snow falls for 1.8 days and regularly aggregates up to 0.43" (11mm) of snow. Throughout the year, there are 14.8 snowfall days, and 3.5" (89mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 24min of daylight.On the first day of December, sunrise is at 7:05 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:45 pm EST.
Sunshine
The average sunshine in December 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. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for the ordinary person.Note: The average daily UV index of 2 in December transforms into the following instructions:
Prolonged exposure to sunlight rarely troubles the majority, but constant protection is vital for babies, children, and fair-skinned people. The solar radiation around mid-day is intense; avoid the Sun and stay safe. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What are the most humid months?
What is the average humidity in December?
How many days does it rain in December in Mainland?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When is the sunrise / sunset in December?
How long on average sun shines in December?
What is the month with the lowest UV index?
How high is the UV index in December in Mainland?
Average temperature in December
Mainland, PA
- Average high temperature in December: 42.1°F
The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is January (35.6°F).
- Average low temperature in December: 30.7°F
The month with the highest average low temperature is July (66.9°F).
The coldest month (with the lowest average low temperature) is January (23.5°F).
Average pressure in December
Mainland, 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
Mainland, PA
- Average wind speed in December: 7.5mph
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
Mainland, PA
- Average humidity in December: 79%
The months with the highest relative humidity are February, October and December (79%).
The months with the lowest relative humidity are April, July and August (73%).
Average rainfall in December
Mainland, PA
- Average rainfall in December: 1.02"
The wettest month (with the highest rainfall) is July (1.3").
The driest month (with the least rainfall) is September (0.59").
Average rainfall days in December
Mainland, PA
- Average rainfall days in December: 7.3 days
The month with the highest number of rainy days is July (13.8 days).
The months with the least rainy days are January and February (6.3 days).
Average snowfall in December
Mainland, PA
- Average snowfall in December: 0.43"
The month with the highest snowfall is March (1.02").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Mainland, PA
- Average snowfall days in December: 1.8 days
The month with the highest number of snowfall days is January (4.6 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Mainland, 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 42min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in December
Mainland, PA
- Average sunshine days in December: 21.7 days
The month with the most sunshine days is November (22.3 days).
The month with the least sunshine days is July (13.9 days).
Average UV index in December
Mainland, 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
Mainland, PA
- Average cloud cover in December: 47
The month with the most cloud cover is February (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in December
Mainland, 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).
Mainland, Pennsylvania, USA
Weather forecast for your location
2. Allow the app to use your location