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
During Mercersburg's transition into December, the average high-temperature lessens, moving from a fresh 50.4°F (10.2°C) in November to a wintry 40.8°F (4.9°C). An average low-temperature of 28.9°F (-1.7°C) is noted during the nights in December in Mercersburg.Humidity
The months with the highest humidity are February, May, October and December, with an average relative humidity of 79%.Rainfall
In Mercersburg, in December, during 11.1 rainfall days, 2.52" (64mm) of precipitation is typically accumulated. In Mercersburg, during the entire year, the rain falls for 170.5 days and collects up to 31.02" (788mm) of precipitation.Snowfall
Months with snowfall in Mercersburg are January through April, October through December. In Mercersburg, Pennsylvania, in December, during 5.9 snowfall days, 2.52" (64mm) of snow is typically accumulated. In Mercersburg, during the entire year, snow falls for 33.6 days and aggregates up to 17.91" (455mm) of snow.Daylight
The month with the shortest days in Mercersburg is December, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 7:14 am and sunset at 4:47 pm. On the last day of December, in Mercersburg, Pennsylvania, sunrise is at 7:32 am and sunset at 4:57 pm EST.
Sunshine
In December, the average sunshine is 4.7h.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 reading of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for the ordinary person.Note: A maximum daily UV index of 2 during December morphs into the following directions:
Prolonged exposure to sunlight rarely troubles the majority, but constant protection is vital for babies, children, and fair-skinned people. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
Frequently asked questions
How cold does it get in Mercersburg in December?
What are the most humid months in Mercersburg?
What is the average humidity in December in Mercersburg?
How many days does it rain in December in Mercersburg?
How much does it snow in Mercersburg in December?
What is the month with the shortest days in Mercersburg?
How many hours of daylight does Mercersburg have in December?
When is the sunrise / sunset in December in Mercersburg?
How long on average sun shines in December in Mercersburg?
When is the lowest UV index in Mercersburg?
What is the UV index reading in December in Mercersburg?
Average temperature in December
Mercersburg, PA
- Average high temperature in December: 40.8°F
The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (35.2°F).
- Average low temperature in December: 28.9°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (22.1°F).
Average pressure in December
Mercersburg, PA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in December
Mercersburg, PA
- Average wind speed in December: 6.8mph
The windiest month (with the highest average wind speed) is January (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).
Average humidity in December
Mercersburg, PA
- Average humidity in December: 79%
The months with the highest relative humidity are February, May, October and December (79%).
The months with the lowest relative humidity are April and July (75%).
Average rainfall in December
Mercersburg, PA
- Average rainfall in December: 2.52"
The wettest month (with the highest rainfall) is May (3.19").
The driest month (with the least rainfall) is September (2.05").
Average rainfall days in December
Mercersburg, PA
- Average rainfall days in December: 11.1 days
The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is November (9.9 days).
Average snowfall in December
Mercersburg, PA
- Average snowfall in December: 2.52"
The month with the highest snowfall is January (5.2").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Mercersburg, PA
- Average snowfall days in December: 5.9 days
The month with the highest number of snowfall days is January (9.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Mercersburg, PA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
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 30min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).
Average sunshine days in December
Mercersburg, PA
- Average sunshine days in December: 15.1 days
The month with the most sunshine days is November (18 days).
The month with the least sunshine days is May (10.3 days).
Average UV index in December
Mercersburg, PA
- Average UV index in December: 2
The months with the highest UV index are May, 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
Mercersburg, PA
- Average cloud cover in December: 50
The months with the most cloud cover are January, February and December (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in December
Mercersburg, PA
- Average visibility in December: 5mi
The months with the highest visibility are April, June, July and November (6mi).
The months with the lowest visibility are January, February, March, May, August, September, October and December (5mi).
Mercersburg, Pennsylvania, USA
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