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
The average high-temperature decreases in December, shifting from a fresh 50.9°F (10.5°C) in November to a wintry 41.9°F (5.5°C). Mortonville, during the nights of December, experiences an average temperature drop to a subzero cold 30.6°F (-0.8°C).Humidity
In Mortonville, the average relative humidity in December is 80%.Rainfall
In December, the rain falls for 8.7 days. Throughout December, 1.54" (39mm) of precipitation is accumulated. In Mortonville, during the entire year, the rain falls for 138.3 days and collects up to 19.76" (502mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Mortonville, Pennsylvania, in December, during 2.7 snowfall days, 1.14" (29mm) of snow is typically accumulated. Throughout the year, there are 19.6 snowfall days, and 7.64" (194mm) 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 7:06 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 4:48 pm EST.
Sunshine
In Mortonville, the average sunshine in December is 4.7h.UV index
The months with the lowest UV index in Mortonville are January through March, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In December, the UV index of 2 transforms into the following advice:
Children, babies, and those with sensitive skin should always be shielded from long periods of sun exposure. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades. Notice this! Nearly double the intensity of the Sun's UV radiation can be caused by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold does it get in December?
What is the average humidity in December?
How many days does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Mortonville have in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Mortonville have in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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
Mortonville, 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).
Mortonville, Pennsylvania, USA
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