December weather forecastBullis Mills, PA
December
Weather in December
December, the first month of the winter in Bullis Mills, is also an icy month, with an average temperature varying between 33.8°F (1°C) and 23.9°F (-4.5°C).Temperature
December involves a decrease in temperature, down from a frosty 43.5°F (6.4°C) in November to a wintry 33.8°F (1°C). Throughout the month of December, Bullis Mills witnesses an average low-temperature of 23.9°F (-4.5°C).Humidity
In Bullis Mills, the average relative humidity in December is 88%.Rainfall
In Bullis Mills, during December, the rain falls for 8.9 days and regularly aggregates up to 2.52" (64mm) of precipitation. Throughout the year, there are 168.9 rainfall days, and 30" (762mm) of precipitation is accumulated.Snowfall
January through May, October through December are months with snowfall. In December, it is snowing for 18.8 days. Throughout December, 9.25" (235mm) of snow is accumulated. In Bullis Mills, during the entire year, snow falls for 92.6 days and aggregates up to 43.58" (1107mm) of snow.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year in Bullis Mills.On the first day of December, sunrise is at 7:22 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 4:52 pm EST.
Sunshine
In Bullis Mills, the average sunshine in December is 2.5h.UV index
January, February and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: A maximum UV index of 1 in December translates into the following recommendations:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. To avoid the Sun's strongest rays, limit exposure around the mid-day period. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Bullis Mills, PA
- Average high temperature in December: 33.8°F
The warmest month (with the highest average high temperature) is July (78.4°F).
The month with the lowest average high temperature is January (27.9°F).
- Average low temperature in December: 23.9°F
The month with the highest average low temperature is July (55.9°F).
The coldest month (with the lowest average low temperature) is January (15.8°F).
Average pressure in December
Bullis Mills, PA
- Average pressure in December: 30.08"Hg
The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in December
Bullis Mills, PA
- Average wind speed in December: 8.9mph
The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).
Average humidity in December
Bullis Mills, PA
- Average humidity in December: 88%
The months with the highest relative humidity are January and February (89%).
The months with the lowest relative humidity are May, June and July (79%).
Average rainfall in December
Bullis Mills, PA
- Average rainfall in December: 2.52"
The wettest month (with the highest rainfall) is April (3.35").
The driest month (with the least rainfall) is September (1.93").
Average rainfall days in December
Bullis Mills, PA
- Average rainfall days in December: 8.9 days
The month with the highest number of rainy days is May (18.7 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in December
Bullis Mills, PA
- Average snowfall in December: 9.25"
The month with the highest snowfall is February (10.63").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Bullis Mills, PA
- Average snowfall days in December: 18.8 days
The month with the highest number of snowfall days is January (20.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Bullis Mills, PA
- Average daylight in December: 9h and 12min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 2h and 30min
The month with the most sunshine is July (Average sunshine: 9h and 24min).
The month with the least sunshine is January (Average sunshine: 2h and 18min).
Average sunshine days in December
Bullis Mills, PA
- Average sunshine days in December: 7.8 days
The month with the most sunshine days is September (12.4 days).
The month with the least sunshine days is February (5.9 days).
Average UV index in December
Bullis Mills, PA
- Average UV index in December: 1
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, February and December (UV index 1).
Average cloud cover in December
Bullis Mills, PA
- Average cloud cover in December: 77
The month with the most cloud cover is January (Cloud cover 79).
The months with the least cloud cover are July and August (Cloud cover 43).
Average visibility in December
Bullis Mills, PA
- Average visibility in December: 4mi
The months with the highest visibility are March, April, May, June, July, October and November (5mi).
The months with the lowest visibility are January, February, August, September and December (4mi).





