Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The shift from November to December involves a decrease in the average high-temperature, dropping from a fresh 52°F (11.1°C) to a chilly 42.8°F (6°C). In the month of December, the average low-temperature usually rests at a freezing cold 31.3°F (-0.4°C).Humidity
The average relative humidity in December is 78%.Rainfall
In December, the rain falls for 8.3 days. Throughout December, 1.18" (30mm) of precipitation is accumulated. Throughout the year, there are 128.5 rainfall days, and 14.92" (379mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, November and December. In West Chester, during December, snow falls for 2.5 days and regularly aggregates up to 0.59" (15mm) of snow. Throughout the year, in West Chester, there are 18.1 snowfall days, and 5.43" (138mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 7:05 am and sunset at 4:37 pm. On the last day of December, sunrise is at 7:23 am and sunset at 4:47 pm EST.
Sunshine
In West Chester, the average sunshine in December is 4.8h.UV index
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for the average person.Note: In December, a daily maximum UV index of 2 leads to the following instructions:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. To cut down UV radiation exposure by about half, sport a wide-brim hat. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
How many days does it rain in December?
How much does it snow in December?
What is the month with the shortest days?
How many hours of daylight does West Chester have in December?
When are sunrise and sunset in December?
How long on average sun shines in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
West Chester, PA
- Average high temperature in December: 42.8°F
The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (36.5°F).
- Average low temperature in December: 31.3°F
The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (24.4°F).
Average pressure in December
West Chester, PA
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in December
West Chester, PA
- Average wind speed in December: 8mph
The windiest month (with the highest average wind speed) is March (8.6mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).
Average humidity in December
West Chester, PA
- Average humidity in December: 78%
The months with the highest relative humidity are February and October (79%).
The month with the lowest relative humidity is April (73%).
Average rainfall in December
West Chester, PA
- Average rainfall in December: 1.18"
The wettest month (with the highest rainfall) is August (2.01").
The driest month (with the least rainfall) is January (0.83").
Average rainfall days in December
West Chester, PA
- Average rainfall days in December: 8.3 days
The month with the highest number of rainy days is July (15.3 days).
The month with the least rainy days is January (5.7 days).
Average snowfall in December
West Chester, PA
- Average snowfall in December: 0.59"
The month with the highest snowfall is March (1.54").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
West Chester, PA
- Average snowfall days in December: 2.5 days
The month with the highest number of snowfall days is January (5.5 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
West Chester, PA
- Average daylight in December: 9h and 2min
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 5min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in December
West Chester, PA
- Average sunshine days in December: 20.5 days
The month with the most sunshine days is November (21.7 days).
The month with the least sunshine days is August (13.1 days).
Average UV index in December
West Chester, PA
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in December
West Chester, PA
- Average cloud cover in December: 48
The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in December
West Chester, PA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).
West Chester, Pennsylvania, USA
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