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
December ushers in a slight temperature change, with average high-temperatures reducing from November's frosty 48.4°F (9.1°C) to a wintry 38.8°F (3.8°C). Rockhill cools down to an average low-temperature of 27.5°F (-2.5°C) throughout the month of December.Humidity
In December, the average relative humidity is 81%.Rainfall
In Rockhill, in December, during 10.9 rainfall days, 2.36" (60mm) of precipitation is typically accumulated. In Rockhill, during the entire year, the rain falls for 164.3 days and collects up to 28.19" (716mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In Rockhill, in December, during 7.7 snowfall days, 2.56" (65mm) of snow is typically accumulated. Throughout the year, there are 40.6 snowfall days, and 17.91" (455mm) 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 7:15 am and sunset at 4:46 pm. On the last day of December, sunrise is at 7:34 am and sunset at 4:55 pm EST.
Sunshine
In Rockhill, the average sunshine in December is 4.3h.UV index
The months with the lowest UV index are January through March, October through 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 average individuals.Note: In December, the maximum UV index of 2 suggests these recommendations:
While most people are not greatly affected by extended sun exposure, those with fair skin, babies, and children must always have protection. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. 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 does it get in Rockhill in December?
What is the average humidity in December?
How much does it rain in December?
How much does it snow in December?
What is the month with the shortest days in Rockhill?
What is the average length of the day in December?
When are sunrise and sunset in December?
How many hours of sunshine does Rockhill have in December?
When is the lowest UV index?
How high is the UV index in December?
Average temperature in December
Rockhill, PA
- Average high temperature in December: 38.8°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in December: 27.5°F
The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is January (20.1°F).
Average pressure in December
Rockhill, 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
Rockhill, PA
- Average wind speed in December: 7.1mph
The windiest month (with the highest average wind speed) is January (7.8mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).
Average humidity in December
Rockhill, PA
- Average humidity in December: 81%
The month with the highest relative humidity is February (82%).
The month with the lowest relative humidity is July (75%).
Average rainfall in December
Rockhill, PA
- Average rainfall in December: 2.36"
The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is September (1.85").
Average rainfall days in December
Rockhill, PA
- Average rainfall days in December: 10.9 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (9.5 days).
Average snowfall in December
Rockhill, PA
- Average snowfall in December: 2.56"
The month with the highest snowfall is January (5.24").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Rockhill, PA
- Average snowfall days in December: 7.7 days
The month with the highest number of snowfall days is January (12.2 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
Rockhill, 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 2min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in December
Rockhill, PA
- Average sunshine days in December: 14.2 days
The month with the most sunshine days is November (16.7 days).
The month with the least sunshine days is May (10.7 days).
Average UV index in December
Rockhill, PA
- Average UV index in December: 2
The months with the highest UV index are May and June (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in December
Rockhill, PA
- Average cloud cover in December: 55
The month with the most cloud cover is January (Cloud cover 56).
The months with the least cloud cover are July and August (Cloud cover 34).
Average visibility in December
Rockhill, PA
- Average visibility in December: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October, November and December (5mi).
Rockhill, Pennsylvania, USA
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