The National Weather Service office in Chicago has one of the longest periods of official weather records , dating back to 1870 , though all the 1870 and 1871 weather records taken at 181 West Washington Street were lost in the Great Chicago Fire . Of the two major airports located in Chicago , Midway Airport began observations in 1928 , and O'Hare Airport began them in 1958 . Both sites have served in the past as the official observation location , the latter being the current official station . Weather data from Midway Airport before July 1 , 1942 , and after January 16 , 1980 , and data from O'Hare Airport before January 17 , 1980 , are not part of the official climate record of Chicago
Great Chicago Fire
Great Chicago Fire
Climate of Chicago