Temperatures in December
It's cold in December in Illinois with an average temperature of 5°C. Temperatures this month range from a low of 1°C to a high of 8°C. At night, you can expect temperatures between -6°C and 0°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Illinois in December. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of December
The month of December starts in Illinois with cold temperatures, averaging around 7°C during the day and nights close to -1°C. There’s little chance of precipitation. The weather is mostly sunny and dry.
Mid-December
By mid-December, the average daytime temperature drops to around 6°C, with nights close to -2°C. Not much precipitation expected during this period. It’s mostly dry with sunshine.
End of December
By the end of December, the average daytime temperature in Illinois will be around 5°C, with nights close to -3°C. A shower might show up, but overall the weather will be dry and sunny. Wear a thick winter coat, jumper, long trousers, hat, and gloves.
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Precipitation in December
In December, there is an average of 55 mm of precipitation, spread over 7 days. Of the total precipitation, about 6,4 cm falls as snow in December. The wind speed is around 4 Bft, mostly coming from the Southwest.
The average precipitation chance is 22% per day this month. Though that seems low, there are also a few days with a higher chance of precipitation.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in December for Illinois. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Illinois in December |
UK | ||
|---|---|---|---|
 Average Temperature |
5°C | 9°C | |
 High Temp |
8°C | 11°C | |
| Low Temp |
1°C | 8°C | |
 Total Precipitation |
55 mm | 67 mm | |
| Rainy Days |
7 days | 10 days | |
 Total Snowfall |
6,4 cm | 1,2 cm | |
| Snowy Days |
3 days | 1 day | |
November
UV index
The UV index is a maximum of 1 this month. That's a low value on the intensity scale of 1 to 11. The risk of sunburn is minimal at this time.
Temperature records for Illinois in December
With 20°C, Illinois hit the highest temperature in the last 10 years in December 2015. The lowest daytime temperature in this month was -18°C in 2022. The extreme night temperatures ranged from a low of -23°C to a high of 16°C.
Check out the climate of Illinois for all months and discover the best travel time
The climate of Illinois is based on weather data from . Other spots, like New York City, Miami or Los Angeles, might have different weather. You can check out all destinations in Illinois for a full picture of the climate.
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Daily Temperature in December in Illinois
This chart shows the average daily temperatures, both day and night, for each day in December in Illinois, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in December in Illinois
The chart below shows the average daily precipitation in December for Illinois, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for December, you can expect around 7 days of rain in Illinois.
Daily Snowfall in December in Illinois
This chart shows the average daily snowfall in December in Illinois, measured in centimetres. The bottom of the chart shows the days of the month. The data is based on historical measurements and gives an idea of the average snowfall in December.
Daily UV Index in December in Illinois
This chart shows the average daily UV index in December in Illinois, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in December in Illinois Over the Years
This chart shows the average temperature in December in Illinois, measured in degrees Celsius, over the past years.
Total Precipitation in December in Illinois Over the Years
This chart shows the average precipitation in December in Illinois, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Snowfall in December in Illinois per year
This chart shows the average snowfall in December in Illinois, measured in centimetres, over the past years.
Daily climate in December for Illinois
Click on a specific day in December for detailed info on the typical weather on that day in Illinois. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in December in Illinois
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Average Weather in Illinois by Month
Click on a month below to see detailed weather info for Illinois. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
