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 onset of December brings a small change in high-temperatures, falling from a cool 50.5°F (10.3°C) in November to a wintry 39°F (3.9°C). In South Jacksonville, December is marked by an average low-temperature of 27.7°F (-2.4°C).Humidity
In South Jacksonville, Illinois, the average relative humidity in December is 78%.Rainfall
The month with the least rainfall in South Jacksonville, Illinois, is December, when the rain falls for 8.1 days and typically collects 1.54" (39mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In South Jacksonville, Illinois, in December, during 5 snowfall days, 1.5" (38mm) of snow is typically accumulated. In South Jacksonville, during the entire year, snow falls for 28.3 days and aggregates up to 9.76" (248mm) of snow.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.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
In South Jacksonville, the average sunshine in December is 4.8h.UV index
The months with the lowest UV index in South Jacksonville are January, February, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for the average person.Note: The UV index of 2 in December translates into these instructions:
Infants, children, and people with sensitive skin should always have protection against lengthy periods of sun exposure. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. During bright days, sunglasses that offer UVA and UVB defense are recommended. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties 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 South Jacksonville?
What is the driest month?
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 long on average sun shines in December?
What are the months with the lowest UV index?
How high is the UV index in December?
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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