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
Onset of December witnesses a reduction in the average high-temperature, falling from a frosty 43.9°F (6.6°C) in November to a cold 32°F (0°C). An average low-temperature of 21.6°F (-5.8°C) is noted during the month of December.Humidity
In Rock City, the average relative humidity in December is 83%.Rainfall
The month with the least rainfall is December, when the rain falls for 6.8 days and typically collects 0.83" (21mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In Rock City, during December, snow falls for 8.2 days and regularly aggregates up to 1.34" (34mm) of snow. Throughout the year, there are 41.8 snowfall days, and 10.43" (265mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 6min of daylight.On the first day of the month, sunrise is at 7:08 am and sunset at 4:26 pm. On the last day of December, sunrise is at 7:27 am and sunset at 4:35 pm CST.
Sunshine
In Rock City, Illinois, the average sunshine in December is 4h.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: The UV index of 1 in December translates into these instructions:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Enhance your sun protection with tightly woven, yet airy clothing. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December in Rock City?
What is the driest month?
How much does it rain in December?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Rock City have in December?
What are the months with the lowest UV index?
What is the UV index reading in December in Rock City?
Average temperature in December
Rock City, IL
- Average high temperature in December: 32°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (25.2°F).
- Average low temperature in December: 21.6°F
The month with the highest average low temperature is July (62.8°F).
The coldest month (with the lowest average low temperature) is January (13.1°F).
Average pressure in December
Rock City, IL
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Rock City, IL
- Average wind speed in December: 9.4mph
The windiest month (with the highest average wind speed) is April (10.3mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in December
Rock City, IL
- Average humidity in December: 83%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).
Average rainfall in December
Rock City, IL
- Average rainfall in December: 0.83"
The wettest month (with the highest rainfall) is June (2.87").
The driest month (with the least rainfall) is December (0.83").
Average rainfall days in December
Rock City, IL
- Average rainfall days in December: 6.8 days
The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (4.9 days).
Average snowfall in December
Rock City, IL
- Average snowfall in December: 1.34"
The month with the highest snowfall is January (2.99").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Rock City, IL
- Average snowfall days in December: 8.2 days
The month with the highest number of snowfall days is January (11.3 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
Rock City, IL
- Average daylight in December: 9h and 1min
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 6min).
- Average sunshine in December: 4h and 0min
The months with the most sunshine are July and August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in December
Rock City, IL
- Average sunshine days in December: 16.7 days
The month with the most sunshine days is November (17.7 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in December
Rock City, IL
- 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 and December (UV index 1).
Average cloud cover in December
Rock City, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in December
Rock City, IL
- Average visibility in December: 6mi
The months with the highest visibility are March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, February, July and August (5mi).
Rock City, Illinois, USA
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