Chicago Weather in December

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

This page gives detailed information on the typical December temperature, precipitation, sun, humidity, wind and storms for Chicago. The numbers here are historical averages based on temperature, rain and snow measurements gathered at Chicago Midway Airport and other climate data from Chicago O'Hare International Airport.

Temperature

38 °F	December average high	3 °C
25 °F	December average low	-4 °C

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

Chicago averages 4 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 ten 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 4 nights. On average, one night in December goes down to 0 °F (-18 °C) or colder.

Precipitation

2.3 in	total precipitation	59 mm
11 days	of rain or snowfall

Half the time, Chicago receives 1.5 to 2.9 inches (38 to 74 mm) of precipitation in December. One in four years has drier weather, while another one in four is wetter.

Snow

7.6 in	total snowfall	19 cm
6 days	with new snow

December's snowfall varies a lot from year to year in Chicago. Between 1.6 and 10 inches (4 to 26 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 nine days this month. The snow normally accumulates to 5 inches (13 cm) or deeper on 2 days.

Sun

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.

Humidity

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 Time	12 am	3 am	6 am	9 am	12 pm	3 pm	6 pm	9 pm
Humidity %	78	79	80	78	70	68	74	77

Wind

11.0 mph

December wind speed average

17.7 kph

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

Storms

2 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.