The current official observations of record for Chicago's weather are taken at O'Hare International Airport. O'Hare (ORD) became the official site for the National Weather Service on Thursday, January 17, 1980. Before this, Midway International Airport (MDW) was the official station of record from Wednesday, July 1, 1942 to January 17, 1980. Before July 1, 1942, records were official at various locations in the city going all the way back to Monday, October 16, 1871. Records before this (back to Saturday, October 15, 1870) were lost during the Great Chicago Fire which began on the evening of Sunday, October 8, 1871. For more information, please visit the National Weather Service, Chicago, at http://www.crh.noaa.gov/lot/?n=office.
