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 weather averages 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

59 °F annual average high 15 °C
41 °F annual average low 5 °C

Chicago's coldest days of the year usually occur in mid January when the daily maximum temperature averages 31 degrees Fahrenheit (-1 degrees Celsius) and the minimum averages 16 °F (-9 °C).

The year's hottest days are normally in mid July. The average temperature peaks then with daily highs of 85 °F (29 °C) and nighttime lows of 64 °F (18 °C).

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

Chicago averages 14 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 43 days annually the thermometer remains below freezing for the entire day.

The temperature drops to 10 °F (-12 °C) or below on 22 nights a year. In an average year, Chicago has 7 nights down to 0 °F (-18 °C) or even colder.

Rainy Weather iconPrecipitation

36.9 in total precipitation 937 mm
124 days of rain or snowfall

August is usually the wettest month of the year in Chicago, while January is the driest.

Snowy Weather iconSnow

36.7 in total snowfall 93.2 cm
29 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 25 days annually.

Sunny Weather iconSun

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.

Humid Weather iconHumidity

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 Time12 am3 am6 am9 am12 pm3 pm6 pm9 pm
Humidity % 77 79 80 69 60 57 63 72

Windy Weather iconWind

10.3 mph wind speed average 16.6 kph

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

Stormy Weather iconStorms

8 days precipitation of 1 inch (25 mm) or more
3 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.


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.

Chicago Weather
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