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
With December's arrival, Mount Joy's weather changes as the average high-temperature falls from a fresh 50.2°F (10.1°C) in November to an icy 41.2°F (5.1°C). During the December nights, an average temperature of 30°F (-1.1°C) is observed.Humidity
In December, the average relative humidity is 79%.Rainfall
In Mount Joy, during December, the rain falls for 8.6 days and regularly aggregates up to 1.1" (28mm) of precipitation. Throughout the year, there are 132.7 rainfall days, and 15.35" (390mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, October through December. In Mount Joy, in December, snow falls for 3.4 days, with typically accumulated 0.94" (24mm) of snow. In Mount Joy, during the entire year, snow falls for 19.3 days and aggregates up to 6.5" (165mm) 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 the month, sunrise is at 7:09 am and sunset at 4:41 pm. On the last day of December, sunrise is at 7:28 am and sunset at 4:50 pm EST.
Sunshine
The average sunshine in December in Mount Joy is 4.8h.UV index
The months with the lowest UV index 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 exposure to the Sun's UV rays for the average person.Note: The maximum daily UV index of 2 in December interprets into the following recommendations:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December?
How much does it rain in Mount Joy in December?
How many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When are sunrise and sunset in December?
How many hours of sunshine does Mount Joy have in December?
What are the months with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Mount Joy, PA
- Average high temperature in December: 41.2°F
The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (35.1°F).
- Average low temperature in December: 30°F
The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in December
Mount Joy, 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
Mount Joy, PA
- Average wind speed in December: 8.1mph
The windiest month (with the highest average wind speed) is March (8.8mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).
Average humidity in December
Mount Joy, PA
- Average humidity in December: 79%
The month with the highest relative humidity is May (81%).
The months with the lowest relative humidity are March and April (76%).
Average rainfall in December
Mount Joy, PA
- Average rainfall in December: 1.1"
The wettest month (with the highest rainfall) is August (1.97").
The driest month (with the least rainfall) is September (0.91").
Average rainfall days in December
Mount Joy, PA
- Average rainfall days in December: 8.6 days
The month with the highest number of rainy days is May (15.7 days).
The months with the least rainy days are January and November (6.6 days).
Average snowfall in December
Mount Joy, PA
- Average snowfall in December: 0.94"
The month with the highest snowfall is January (2.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Mount Joy, PA
- Average snowfall days in December: 3.4 days
The month with the highest number of snowfall days is January (5.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Mount Joy, 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 5min
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 30min).
Average sunshine days in December
Mount Joy, PA
- Average sunshine days in December: 19.2 days
The month with the most sunshine days is November (21.4 days).
The month with the least sunshine days is July (11.8 days).
Average UV index in December
Mount Joy, PA
- Average UV index in December: 2
The months with the highest UV index are June and July (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
Mount Joy, PA
- Average cloud cover in December: 49
The months with the most cloud cover are February and December (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in December
Mount Joy, 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).
Mount Joy, Pennsylvania, USA
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