w1.weather.gov/data/obhistory/KORD.html
Weather Observations for the past three days
NOAA/NWS

Weather table includes date, time, wind speed and direction, visibility, weather, sky conditions, air temperature, dew point, 6-hour maximum and minimum, relative humidity, wind chill, heat index, pressure (altimeter/in), pressure (sea level/mb), precipitation (in. 1 hr, 3 hr 6 hr)

CHICAGO 3 DAY O’HARE KORD
w1.weather.gov/data/obhistory/KORD.html

CHICAGO EXECUTIVE KPWK
w1.weather.gov/data/obhistory/KPWK.html

WAUKEGAN NATIONAL KUGN
w1.weather.gov/data/obhistory/KUGN.html

chicagoweatherstation.com

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Surface Observations Map
Includes, radar, 3-day weather history and more.