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
In the transition to December, South Jacksonville observes a drop in the average high-temperature, moving from a cool 50.5°F (10.3°C) in November to a wintry 39°F (3.9°C). Nighttime temperature lowers to an average of 27.7°F (-2.4°C) in December.Humidity
In December, the average relative humidity in South Jacksonville, Illinois, is 78%.Rainfall
The month with the least rainfall in South Jacksonville is December, when the rain falls for 8.1 days and typically collects 1.54" (39mm) of precipitation.Snowfall
January through April, October through December are months with snowfall in South Jacksonville. In South Jacksonville, in December, snow falls for 5 days, with typically accumulated 1.5" (38mm) of snow. Throughout the year, there are 28.3 snowfall days, and 9.76" (248mm) of snow is accumulated.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year in South Jacksonville.On the first day of the month, sunrise is at 7:03 am and sunset at 4:37 pm. On the last day of December, sunrise is at 7:21 am and sunset at 4:46 pm CST.
Sunshine
The average sunshine in December in South Jacksonville, Illinois, is 4.8h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the average person.Note: The UV index of 2 during December leads to these advisories:
Extended sunlight exposure does not pose significant problems for most people, except for children, infants, and people with fair skin who always need shielding. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes. Be watchful! The reflection of snow can enhance the intensity of the Sun's UV radiation nearly double.
Frequently asked questions
How cold is it in South Jacksonville in December?
What is the average humidity in December in South Jacksonville?
What is the driest month in South Jacksonville?
How much does it rain in South Jacksonville in December?
How much does it snow in South Jacksonville in December?
What is the month with the shortest days in South Jacksonville?
What is the average length of the day in December in South Jacksonville?
When is the sunrise / sunset in December in South Jacksonville?
How many hours of sunshine does South Jacksonville have in December?
What is the month with the lowest UV index in South Jacksonville?
How high is the UV index in December in South Jacksonville?
Average temperature in December
South Jacksonville, IL
- Average high temperature in December: 39°F
The warmest month (with the highest average high temperature) is July (83.3°F).
The month with the lowest average high temperature is January (33.4°F).
- Average low temperature in December: 27.7°F
The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (21°F).
Average pressure in December
South Jacksonville, IL
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
South Jacksonville, IL
- Average wind speed in December: 9.6mph
The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest month (with the lowest average wind speed) is July (6.1mph).
Average humidity in December
South Jacksonville, IL
- Average humidity in December: 78%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
South Jacksonville, IL
- Average rainfall in December: 1.54"
The wettest month (with the highest rainfall) is June (3.58").
The driest month (with the least rainfall) is December (1.54").
Average rainfall days in December
South Jacksonville, IL
- Average rainfall days in December: 8.1 days
The month with the highest number of rainy days is May (18 days).
The months with the least rainy days are January and February (7.1 days).
Average snowfall in December
South Jacksonville, IL
- Average snowfall in December: 1.5"
The month with the highest snowfall is January (3.58").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
South Jacksonville, IL
- Average snowfall days in December: 5 days
The month with the highest number of snowfall days is January (9.6 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
South Jacksonville, IL
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
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 June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in December
South Jacksonville, IL
- Average sunshine days in December: 18.5 days
The month with the most sunshine days is December (18.5 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in December
South Jacksonville, IL
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
South Jacksonville, IL
- Average cloud cover in December: 49
The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are June, July, August and September (Cloud cover 29).
Average visibility in December
South Jacksonville, IL
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
South Jacksonville, Illinois, USA
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