December weather forecastDerry, PA
December
Weather in December
December, the first month of the winter in Derry, is still a cold month, with an average temperature varying between 38.3°F (3.5°C) and 27.1°F (-2.7°C).Temperature
In December, the average high-temperature decreases from a chilly 47.7°F (8.7°C) in November to an icy 38.3°F (3.5°C). The average low-temperature during December nights is a freezing cold 27.1°F (-2.7°C).Humidity
In Derry, the average relative humidity in December is 85%.Rainfall
In Derry, in December, it is raining for 10.1 days, with typically 1.73" (44mm) of accumulated precipitation. Throughout the year, there are 156.2 rainfall days, and 19.45" (494mm) of precipitation is accumulated.Snowfall
January through May, October through December are months with snowfall. In Derry, during December, snow falls for 9.5 days and regularly aggregates up to 3.9" (99mm) of snow. Throughout the year, there are 49.9 snowfall days, and 18.11" (460mm) 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 the month, sunrise is at 7:21 am and sunset at 4:51 pm. On the last day of December, sunrise is at 7:39 am and sunset at 5:01 pm EST.
Sunshine
In Derry, the average sunshine in December is 3.5h.UV index
With an average maximum UV index of 1, December is the month with the lowest UV index. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation for average individuals.Note: A daily maximum UV index of 1 in December translates into the following instructions:
Infants, children, and people with sensitive skin should always have protection against lengthy periods of sun exposure. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Watch out! The Sun's UV radiation can be nearly magnified twofold due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Derry, PA
- Average high temperature in December: 38.3°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (32.2°F).
- Average low temperature in December: 27.1°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 (19.8°F).
Average pressure in December
Derry, 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
Derry, PA
- Average wind speed in December: 8.6mph
The windiest month (with the highest average wind speed) is January (9.2mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in December
Derry, PA
- Average humidity in December: 85%
The months with the highest relative humidity are January and February (86%).
The months with the lowest relative humidity are April, July and August (78%).
Average rainfall in December
Derry, PA
- Average rainfall in December: 1.73"
The wettest month (with the highest rainfall) is May (2.32").
The driest month (with the least rainfall) is November (1.02").
Average rainfall days in December
Derry, PA
- Average rainfall days in December: 10.1 days
The month with the highest number of rainy days is May (19.8 days).
The month with the least rainy days is January (7.6 days).
Average snowfall in December
Derry, PA
- Average snowfall in December: 3.9"
The month with the highest snowfall is January (3.94").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Derry, PA
- Average snowfall days in December: 9.5 days
The month with the highest number of snowfall days is January (13.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Derry, 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: 3h and 30min
The months with the most sunshine are July and August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).
Average sunshine days in December
Derry, PA
- Average sunshine days in December: 13.3 days
The month with the most sunshine days is November (18 days).
The month with the least sunshine days is May (8.9 days).
Average UV index in December
Derry, PA
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Derry, PA
- Average cloud cover in December: 65
The month with the most cloud cover is January (Cloud cover 70).
The month with the least cloud cover is August (Cloud cover 36).
Average visibility in December
Derry, PA
- Average visibility in December: 5mi
The months with the highest visibility are April and November (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October and December (5mi).
