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 arrival of December indicates a decrease in the average high-temperature, moving from a frosty 43.9°F (6.6°C) in November to an icy 32°F (0°C). Rock City experiences a steady low-temperature of 21.6°F (-5.8°C) throughout December.Humidity
The average relative humidity in December in Rock City is 83%.Rainfall
December is the month with the least rainfall. Rain falls for 6.8 days and accumulates 0.83" (21mm) of precipitation.Snowfall
Months with snowfall in Rock City are January through April, October through December. In Rock City, in December, snow falls for 8.2 days, with typically accumulated 1.34" (34mm) of snow. In Rock City, during the entire year, snow falls for 41.8 days and aggregates up to 10.43" (265mm) of snow.Daylight
December has the shortest days of the year in Rock City, 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, in Rock City, sunrise is at 7:27 am and sunset at 4:35 pm CST.
Sunshine
In Rock City, the average sunshine in December is 4h.UV index
January and December, with an average maximum UV index of 1, are months with the lowest UV index in Rock City. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: A maximum daily UV index of 1 during December morphs into the following directions:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Frequently asked questions
How cold is December in Rock City?
What is the average humidity in December in Rock City?
What is the driest month in Rock City?
How much does it rain in Rock City in December?
How many days does it snow in December in Rock City?
What is the month with the shortest days in Rock City?
What is the average length of the day in December in Rock City?
When are sunrise and sunset in December in Rock City?
How long on average sun shines in December in Rock City?
When is the lowest UV index in Rock City?
How high is the UV index 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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