Chicago Weather Averages

Chicago, Illinois experiences a wide range of temperatures, with blasts of cold weather in winter and hot days in summer. Meanwhile precipitation in the city remains fairly steady. Year round, one in three days have some rain or snow. The rain comes down more heavily though from May to August.

This page gives detailed information on the annual temperature, precipitation, sun, humidity, wind and storms averages 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

61 °F	annual average high	16 °C
44 °F	annual average low	7 °C

Chicago's coldest days of the year usually occur in the second half of January when the daily maximum temperature averages 32 degrees Fahrenheit (0 degrees Celsius) and the minimum averages 19 °F (-7 °C).

The year's hottest days are normally in mid July. The average temperature peaks then with daily highs of 86 °F (30 °C) and nighttime lows of 68 °F (20 °C).

145 days	70 °F max. or more (21 °C)
108 days	32 °F min. or less (0 °C)

Chicago averages 21 days a year when the thermometer reaches into the 90s °F (over 32 °C). The temperature can climb briefly above 100 °F (38 °C) although days that hot don't occur every year. Typically on 39 days annually the thermometer remains below freezing for the entire day.

The temperature drops to 10 °F (-12 °C) or below on 16 nights a year. In an average year, Chicago has 4 nights down to 0 °F (-18 °C) or even colder.

Precipitation

40.9 in	total precipitation	1038 mm
127 days	of rain or snowfall

May is usually the wettest month of the year in Chicago, while winter months are the driest.

Snow

38.4 in	total snowfall	98 cm
28 days	with new snow

Most years, it snows in Chicago from November to April. The snowpack accumulates to at least 3 inches (8 cm) deep on an average of 26 days annually.

Sun

54 %	sunshine
84 days	clear skies

The sun's rays reach the ground in Chicago during 54 percent of daylight hours on average year round, for a total of 2407 hours annually. Typically on 84 days a year the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in Chicago averages 12 hours and 12 minutes a day. The shortest days of the year in mid December have 9 hours and 8 minutes of daylight. The year's longest days in mid June last 15:13 from sunrise to sunset.

Humidity

70 %	average humidity

The annual average for relative humidity in Chicago ranges throughout the day from 80 percent at 6:00 am to 57 percent at 3:00 pm.

Local Time	12 am	3 am	6 am	9 am	12 pm	3 pm	6 pm	9 pm
Humidity %	77	79	80	69	60	57	63	72

Wind

10.3 mph

wind speed average

16.6 kph

April is usually the windiest month for Chicago, while the wind is calmest during August.

Storms

10 days	precipitation of 1 inch (25 mm) or more
4 days	snowfall of 3 inches (8 cm) or more
38 days	with thunderstorms a year

Storms that blanket Chicago in over 10 inches (25 cm) of snow during a single day appear about once a decade.

Thunderstorms usually pass over Chicago from March to November, although they can appear in any month.