National Weather Service Weather Forecast Office

HEAT INDEX VALUES COULD REACH OR EXCEED 105 DEGREES IN  CHICAGO THIS
WEEK...WITH HIGHEST CONFIDENCE IN THIS OCCURRING BEING ON THURSDAY.
IT IS POSSIBLE THAT HEAT INDEX VALUES COULD APPROACH 105 DEGREES ON
WEDNESDAY AND FRIDAY AS WELL. LOOKING BACK AT THE PERIOD 1990
THROUGH 2010 IT TURNS OUT THAT DAYS THAT SAW THE HEAT INDEX IN
CHICAGO OFFICIALLY REACH 105 DEGREES WERE QUITE RARE. IN
FACT...THERE HAVE ONLY BEEN 31 DAYS WHERE THE HEAT INDEX OFFICIALLY
REACH 105 DEGREES AT OHARE INTERNATIONAL AIRPORT...THE OFFICIAL
RECORDING STATION FOR CHICAGO. IN ORDER TO FIND THE LAST HOURLY
OBSERVATION WITH A HEAT INDEX OF AT LEAST 105 IN CHICAGO...ONE WOULD
HAVE TO LOOK BACK TO 6 PM ON AUGUST 2ND 2006.

HERE IS A LIST OF THE ALL OF THE DAYS GOING BACK TO 1990 THAT
CHICAGO OHARE HAS SEEN HEAT INDEX READINGS OF AT LEAST 105
DEGREES.

DATE         PEAK HEAT HOURS WITH H.I.
               INDEX       ABOVE 105F
08/02/2006......105.............4
08/01/2006......105.............4
07/31/2006......108.............5
07/17/2006......107.............4

07/24/2005......107.............5

08/21/2003......105.............3
08/01/2003......105.............1

07/21/2002......107.............7

08/07/2001......105.............1
07/23/2001......107.............1

07/30/1999......114.............12
07/29/1999......113.............8
07/22/1999......105.............1
07/04/1999......105.............1
07/03/1999......105.............1

06/27/1998......105.............1

07/26/1997......115.............6

08/16/1995......105.............1
08/14/1995......107.............3
08/13/1995......105.............2
08/12/1995......111.............6
07/15/1995......105.............2
07/14/1995......116.............11
07/13/1995......118.............12

07/06/1994......105.............1
07/05/1994......107.............2

07/18/1993......109.............2

08/09/1992......105.............2

07/22/1991......107.............2

08/27/1990......105.............1
07/04/1990......109.............8


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