December weather forecastSouth Williamsport, PA
December
Weather in December
December, the first month of the winter in South Williamsport, is also an icy month, with an average temperature varying between 36.7°F (2.6°C) and 26.6°F (-3°C).Temperature
The move into December indicates a reduction in the average high-temperature, down from November's frosty 46.2°F (7.9°C) to a wintry 36.7°F (2.6°C). South Williamsport registers a consistent average low-temperature of 26.6°F (-3°C) during December.Humidity
In December, the average relative humidity is 83%.Rainfall
In South Williamsport, in December, during 10.6 rainfall days, 1.14" (29mm) of precipitation is typically accumulated. In South Williamsport, during the entire year, the rain falls for 145.2 days and collects up to 16.57" (421mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In South Williamsport, in December, during 8.1 snowfall days, 1.38" (35mm) of snow is typically accumulated. In South Williamsport, Pennsylvania, during the entire year, snow falls for 39.1 days and aggregates up to 7.56" (192mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 18min of daylight.On the first day of December, sunrise is at 7:14 am and sunset at 4:39 pm. On the last day of the month, sunrise is at 7:33 am and sunset at 4:49 pm EST.
Sunshine
In South Williamsport, the average sunshine in December is 3.9h.UV index
The months with the lowest UV index are January through March, October through December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for the average person.Note: The UV index of 2 during December translates into the following guidance:
Children must always have sun protection, unlike most people, who can tolerate up to an hour in the sun without any burns. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Notice! The UV radiation of the Sun can be intensified nearly twofold due to the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
South Williamsport, PA
- Average high temperature in December: 36.7°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (30.6°F).
- Average low temperature in December: 26.6°F
The month with the highest average low temperature is July (59.2°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in December
South Williamsport, PA
- Average pressure in December: 30.09"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
South Williamsport, PA
- Average wind speed in December: 7mph
The windiest months (with the highest average wind speed) are January, March and April (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in December
South Williamsport, PA
- Average humidity in December: 83%
The month with the highest relative humidity is February (84%).
The months with the lowest relative humidity are April and July (77%).
Average rainfall in December
South Williamsport, PA
- Average rainfall in December: 1.14"
The wettest month (with the highest rainfall) is April (1.93").
The driest month (with the least rainfall) is November (0.94").
Average rainfall days in December
South Williamsport, PA
- Average rainfall days in December: 10.6 days
The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is February (7.5 days).
Average snowfall in December
South Williamsport, PA
- Average snowfall in December: 1.38"
The month with the highest snowfall is February (2.28").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
South Williamsport, PA
- Average snowfall days in December: 8.1 days
The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
South Williamsport, PA
- Average daylight in December: 9h and 18min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in December: 3h and 54min
The month with the most sunshine is July (Average sunshine: 10h and 6min).
The months with the least sunshine are January and February (Average sunshine: 3h and 42min).
Average sunshine days in December
South Williamsport, PA
- Average sunshine days in December: 15.5 days
The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in December
South Williamsport, PA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in December
South Williamsport, PA
- Average cloud cover in December: 59
The months with the most cloud cover are January and February (Cloud cover 60).
The month with the least cloud cover is July (Cloud cover 35).
Average visibility in December
South Williamsport, PA
- Average visibility in December: 5mi
The month with the highest visibility is April (6mi).
The month with the lowest visibility is September (4mi).
