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
A shift in Rockdale's weather is observed as November turns into December, with the average high temperature reducing from a chilly 47.1°F (8.4°C) to a cold 35.1°F (1.7°C). Throughout December, Rockdale registers a consistent average low-temperature of 25°F (-3.9°C).Humidity
In Rockdale, the average relative humidity in December is 82%.Rainfall
In Rockdale, in December, it is raining for 8.1 days, with typically 1.69" (43mm) of accumulated precipitation. Throughout the year, there are 153.6 rainfall days, and 32.72" (831mm) of precipitation is accumulated.Snowfall
January through April, November and December are months with snowfall. In Rockdale, during December, snow falls for 8 days and regularly aggregates up to 2.4" (61mm) of snow. In Rockdale, during the entire year, snow falls for 38.2 days and aggregates up to 14.61" (371mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 7:00 am and sunset at 4:23 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 4:32 pm CST.
Sunshine
In December, the average sunshine is 4.1h.UV index
January and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a low health risk from unprotected exposure to Sun's UV rays for average individuals.Note: A daily maximum UV index of 1 in December translates into the following instructions:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Take to heart! Snow reflection can almost magnify the Sun's UV radiation twofold.
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 many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When are sunrise and sunset in December?
How many hours of sunshine does Rockdale have in December?
What is the month with the lowest UV index in Rockdale?
How high is the UV index in December?
Average temperature in December
Rockdale, IL
- Average high temperature in December: 35.1°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.3°F).
- Average low temperature in December: 25°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).
Average pressure in December
Rockdale, 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 (29.92"Hg).
Average wind speed in December
Rockdale, IL
- Average wind speed in December: 8.9mph
The windiest month (with the highest average wind speed) is April (9.7mph).
The calmest month (with the lowest average wind speed) is August (5.9mph).
Average humidity in December
Rockdale, IL
- Average humidity in December: 82%
The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is October (73%).
Average rainfall in December
Rockdale, IL
- Average rainfall in December: 1.69"
The wettest month (with the highest rainfall) is May (4.41").
The driest month (with the least rainfall) is February (1.61").
Average rainfall days in December
Rockdale, IL
- Average rainfall days in December: 8.1 days
The month with the highest number of rainy days is July (17.9 days).
The month with the least rainy days is February (5.7 days).
Average snowfall in December
Rockdale, IL
- Average snowfall in December: 2.4"
The month with the highest snowfall is January (4.33").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Rockdale, IL
- Average snowfall days in December: 8 days
The month with the highest number of snowfall days is January (11.9 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
Rockdale, IL
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 4h and 1min
The month with the most sunshine is August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Rockdale, IL
- Average sunshine days in December: 15.9 days
The month with the most sunshine days is November (18.1 days).
The month with the least sunshine days is June (10.4 days).
Average UV index in December
Rockdale, IL
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Rockdale, IL
- Average cloud cover in December: 58
The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are August and September (Cloud cover 34).
Average visibility in December
Rockdale, 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).
Rockdale, Illinois, USA
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