December weather forecastLilly, PA
December
Weather in December
The first month of the winter, December, is also an icy month in Lilly, Pennsylvania, with an average temperature varying between 26.2°F (-3.2°C) and 36.5°F (2.5°C).Temperature
A shift in the average high-temperature occurs in December, reducing from a chilly 46°F (7.8°C) in November to a wintry 36.5°F (2.5°C). The average nighttime temperature lowers to a freezing cold 26.2°F (-3.2°C) throughout December.Humidity
In December, the average relative humidity is 85%.Rainfall
In Lilly, in December, it is raining for 10.8 days, with typically 2.95" (75mm) of accumulated precipitation. Throughout the year, there are 170 rainfall days, and 33.46" (850mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, October through December. In December, it is snowing for 13.8 days. Throughout December, 7.01" (178mm) of snow is accumulated. In Lilly, during the entire year, snow falls for 70.6 days and aggregates up to 40.12" (1019mm) of snow.Daylight
With an average of 9h and 18min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:18 am and sunset at 4:48 pm. On the last day of December, sunrise is at 7:37 am and sunset at 4:58 pm EST.
Sunshine
In Lilly, the average sunshine in December is 3.4h.UV index
The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: The UV index of 1 in December translates into these instructions:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Beware! Reflection from snow can magnify the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Lilly, PA
- Average high temperature in December: 36.5°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (30.4°F).
- Average low temperature in December: 26.2°F
The month with the highest average low temperature is July (59.5°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in December
Lilly, PA
- Average pressure in December: 30.1"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
Lilly, PA
- Average wind speed in December: 9.3mph
The windiest month (with the highest average wind speed) is January (10mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in December
Lilly, PA
- Average humidity in December: 85%
The month with the highest relative humidity is February (86%).
The months with the lowest relative humidity are April, June and July (78%).
Average rainfall in December
Lilly, PA
- Average rainfall in December: 2.95"
The wettest month (with the highest rainfall) is May (3.62").
The driest month (with the least rainfall) is November (2.01").
Average rainfall days in December
Lilly, PA
- Average rainfall days in December: 10.8 days
The month with the highest number of rainy days is May (19.8 days).
The month with the least rainy days is January (7.7 days).
Average snowfall in December
Lilly, PA
- Average snowfall in December: 7.01"
The month with the highest snowfall is February (8.86").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Lilly, PA
- Average snowfall days in December: 13.8 days
The month with the highest number of snowfall days is January (18 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Lilly, PA
- Average daylight in December: 9h and 18min
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 18min).
- Average sunshine in December: 3h and 24min
The month with the most sunshine is July (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 6min).
Average sunshine days in December
Lilly, PA
- Average sunshine days in December: 9.8 days
The month with the most sunshine days is November (13.5 days).
The months with the least sunshine days are January and February (7.7 days).
Average UV index in December
Lilly, PA
- Average UV index in December: 1
The months with the highest UV index are May, June, July and August (UV index 5).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Lilly, PA
- Average cloud cover in December: 65
The month with the most cloud cover is January (Cloud cover 70).
The months with the least cloud cover are July and August (Cloud cover 39).
Average visibility in December
Lilly, PA
- Average visibility in December: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January and February (4mi).





