December weather forecastWilliamson, PA
December
Weather in December
December, the first month of the winter in Williamson, is also an icy month, with an average temperature varying between 41.2°F (5.1°C) and 28.9°F (-1.7°C).Temperature
The onset of December results in a decrease in the average high-temperature, receding from a fresh 50.5°F (10.3°C) in November to a cold 41.2°F (5.1°C). In Williamson, December nights witness a steady temperature drop to a subzero cold 28.9°F (-1.7°C).Humidity
February, May, October and December, with an average relative humidity of 79%, are the most humid months in Williamson.Rainfall
In Williamson, in December, during 10.3 rainfall days, 2.01" (51mm) of precipitation is typically accumulated. In Williamson, during the entire year, the rain falls for 161.8 days and collects up to 28.07" (713mm) of precipitation.Snowfall
January through April, October through December are months with snowfall in Williamson. In Williamson, Pennsylvania, during December, snow falls for 4.7 days and regularly aggregates up to 2.13" (54mm) of snow. Throughout the year, there are 26.6 snowfall days, and 14.69" (373mm) 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 7:14 am and sunset at 4:46 pm. On the last day of the month, sunrise is at 7:32 am and sunset at 4:56 pm EST.
Sunshine
In Williamson, the average sunshine in December is 4.8h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: A maximum UV index of 2 in December translates into the following recommendations:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Take precaution! The reflection from snow can almost double the UV radiation of the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Williamson, PA
- Average high temperature in December: 41.2°F
The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (35.4°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 (22.5°F).
Average pressure in December
Williamson, 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
Williamson, PA
- Average wind speed in December: 7mph
The windiest month (with the highest average wind speed) is January (7.7mph).
The calmest months (with the lowest average wind speed) are July and August (4.5mph).
Average humidity in December
Williamson, 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
Williamson, PA
- Average rainfall in December: 2.01"
The wettest month (with the highest rainfall) is May (3.15").
The driest month (with the least rainfall) is January (1.85").
Average rainfall days in December
Williamson, PA
- Average rainfall days in December: 10.3 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 days).
Average snowfall in December
Williamson, PA
- Average snowfall in December: 2.13"
The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Williamson, PA
- Average snowfall days in December: 4.7 days
The month with the highest number of snowfall days is January (8.1 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
Williamson, PA
- Average daylight in December: 9h and 24min
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 48min
The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in December
Williamson, PA
- Average sunshine days in December: 17.1 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (10.4 days).
Average UV index in December
Williamson, 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, November and December (UV index 2).
Average cloud cover in December
Williamson, 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 32).
Average visibility in December
Williamson, PA
- Average visibility in December: 5mi
The months with the highest visibility are April, June, July, August and November (6mi).
The months with the lowest visibility are January, February, March, May, September, October and December (5mi).
