Chicago Weather in December

The first substantial snowfalls of winter usually arrive in December at Chicago, Illinois. This is also when temperatures begin to drop below 10 °F (-12 °C).

This page gives detailed information on the typical December weather for Chicago.

You can jump directly to data and descriptions for:

The numbers here are historical averages based on climate data gathered at the Chicago O'Hare International Airport, located in the northwestern part of Chicago.

Temperature Weather iconTemperature

35 °F December average high 2 °C
21 °F December average low -6 °C

In most years, Chicago averages a daily maximum temperature for December that's between 29 and 40 degrees Fahrenheit (-2 to 5 degrees Celsius). The minimum temperature usually falls between 15 and 27 °F (-10 to -3 °C).

The days at Chicago continue to grow colder during December. By the end of the month, the temperature has dropped around 8 °F (5 °C) below what it was at the start.

9 days 40 °F max. or more (4 °C)
13 days 20 °F min. or less (-8 °C)

Chicago averages 3 days this month when the thermometer reaches into the 50s °F (over 10 °C). Temperatures above 60 °F (16 °C) don't happen every year in December. Typically 11 days remain below freezing for the entire day.

Most December nights are below freezing. The thermometer drops to 10 °F (-12 °C) or lower on 6 nights. On average, one or two nights in December go down to 0 °F (-18 °C) or colder.

Rainy Weather iconPrecipitation

2.3 in total precipitation 57 mm
11 days of rain or snowfall

Half the time, Chicago receives 1 to 3 inches (30 to 70 mm) of precipitation in December. One in four years has drier weather, while another one in four is wetter.

Snowy Weather iconSnow

8.5 in total snowfall 21.6 cm
7 days with new snow

December's snowfall varies a lot from year to year in Chicago. Between 3 and 11 inches (8 to 27 cm) of fresh snow arrives in half the years. Less new snow lands in one out of four Decembers, while another twenty-five percent are snowier.

Chicago typically has at least an inch (2.5 cm) of snow on the ground for 10 days this month. The snow normally accumulates to 5 inches (13 cm) or deeper on 2 days.

Sunny Weather iconSun

43 % sunshine
6 days clear skies

The sun's rays reach the ground in Chicago during 43 percent of daylight hours on average in December, for a total of 123 hours in the month. Typically on 6 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in December at Chicago averages 9 hours and 11 minutes a day. The shortest days of the year, from around December 18th to 24th, last 9 hours and 8 minutes from sunrise to sunset.

Humid Weather iconHumidity

76 % December average humidity

December is Chicago's most humid month. The relative humidity usually peaks at 80 percent in the morning then drops to 68 percent by early afternoon.

Local Time12 am3 am6 am9 am12 pm3 pm6 pm9 pm
Humidity % 78 79 80 78 70 68 74 77

Windy Weather iconWind

11.0 mph December wind speed average 17.7 kph

December is a little windier than most other months in Chicago.

Stormy Weather iconStorms

3 days snowfall of 1 inch (2.5 cm) or more
1 day with thunderstorms in December

Every few years, Chicago can get 5 to 10 inches (13 to 25 mm) of snow in one day during December.

Thunderstorms don't show up every year in December.

Reference

These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity and thunderstorm statistics are 1961-1990 normals.

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