History of the Chicago and Rockford weather observation sites

Weather Observations for the City of Chicago

Official Climate Sites

Location	Occupied From	Occupied To	Remarks
181 W Washington St (formerly 162 Washington St)	10/15/1870	10/08/1871	Station abandoned October 8, 1871 in Great Chicago Fire – all records lost.
427 W Randolph St (10 W Randolph prior to 1909)	10/15/1871	6/11/1872	Room rented October 14, regular observations resumes October 16
20 N Wacker Drive (80 S Market prior to 1909)	6/11/1872	6/08/1873
Roanoke Building (formerly Major Block) SE Corner Madison and LaSalle Street)	6/08/1873	1/01/1887
Chicago Opera House SW Corner Clark and Washington	1/01/1887	2/01/1890
Auditorium Tower NE Corner Wabash and Congress	2/01/1890	7/01/1905	Automatic Recording Rain gage installed 1897
U.S. Court House 219 S Dearborn St.	7/01/1905	12/31/1925	Maintained Supplemental Observations through October 15, 1970
University of Chicago Rosenwald Hall 58th St and University Ave	1/01/1926	6/30/1942	Maintained Supplemental Observations through March 31, 1962
Midway Airport South Terminal Building 6200 South Cicero Ave	7/01/1942	1/17/1980	Supplemental Observations were transferred to station Midway 3SW
O’Hare International Airport International Terminal Building	1/17/1980	3/07/1985
O’Hare International Airport Hardstand Operational Building	3/07/1985	1/19/1989
O’Hare International Airport O’Hare Corporate Tower, Rosemont	1/19/1989	2/01/1996
O’Hare International AP	2/01/1996	Present	ASOS installed

Additional Climate records (but not official for Chicago)

Location	Occupied From	Occupied To	Remarks
U.S. Court House 219 S Dearborn St.	1/01/1926	10/15/1970	Previously was official site for Chicago. Observations continued local site’s climate record.
University of Chicago Rosenwald Hall 58th St and University Ave	1/01/1916 and 7/01/1942	12/31/1925 and 3/31/1962	Temporarily was official site for Chicago. Observations continued local site’s climate record.
University of Chicago 5730 S Woodlawn Avenue	4/01/1962	10/31/1994	Previously was official site for Chicago. Observations continued local site’s climate record.
Midway Airport National Airtransport Hangar 5490 South Cicero Ave	2/13/1928	11/03/1932
Midway Airport South Terminal Building 6200 South Cicero Ave	11/03/1932	6/30/1942	Continuation of MDW climate record. Became official cite for Chicago on 7/01/1942.
Midway 3SW Cooperative Observer	1/18/1980	Present	Continuation of MDW climate records after official Chicago site was transferred to O’Hare
O’Hare International Airport International Terminal Building	10/30/1958	1/16/1980	Beginning of ORD climate records. Became official site for city of Chicago on 1/17/1980

Weather Observations for the City of Rockford

Official Climate Sites

Location	Occupied From	Occupied To	Remarks
900 Block, North Main	12/??/1872	10/??/1893	Cooperative Observer, T. D. Robertson (rainfall only)
731 North Court Street	11/??/1893	12/??/1912	Cooperative Observer, H. C. Porter (rainfall only)
1135 North Court Street	1/??/1913	6/01/1918	Cooperative Observer, Dr. John R. Porter (temperature observations added)
731 North Court Street	6/02/1918	7/29/1920	Cooperative Observer, Carson H. Porter
324 Churchill Street	7/30/1920	12/19/1950	Cooperative Observers, F. W. Knowlton and Daughter
Greater Rockford Airport Federal Facilities Building	12/19/1950	7/01/1995	Moved to Airport
Greater Rockford Airport	7/01/1995	Present	ASOS installed

Additional Climate records (but not official for Rockford)

Location	Occupied From	Occupied To	Remarks
324 Churchill Street	12/19/1950	9/23/1953	Cooperative Observers, Previously was official location for Rockford climate files.
2221 North Winnebago	9/24/1953	6/30/1957	Continuation of cooperative observer climate record after observer obtained new residence.

National Weather Service Weather Forecast Office