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Excessive Heat Warning — Northern Cook, IL, Central Cook, IL, Southern Cook, IL, Lake, IN, Porter, IN, Newton, IN, Jasper, IN, Benton, IN
Issued
Expires
12:00 AM CDT · Fri, Jul 3 2026
Issuing Office
NWS KLOT

Affected Areas

Northern Cook, IL Central Cook, IL Southern Cook, IL Lake, IN Porter, IN Newton, IN Jasper, IN Benton, IN

Official Bulletin

172
WWUS73 KLOT 301406
NPWLOT

URGENT - WEATHER MESSAGE
National Weather Service Chicago IL
906 AM CDT Tue Jun 30 2026

ILZ003>006-008-010>013-019>021-023-032-033-039-106>108-INZ001-002-010-011-019-010015-
/O.CON.KLOT.XH.W.0001.000000T0000Z-260703T0500Z/
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-La
Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-Northern
Will-Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-
Benton-
Including the cities of Downers Grove, Crystal Lake, Valparaiso,
Buffalo Grove, Gilman, Dixon, Sycamore, Gurnee, Carol Stream,
Paxton, Peotone, Kankakee, Portage, Gary, McHenry, Roselawn,
Mokena, Waukegan, Chesterton, Wheaton, Oxford, Plano, Pontiac,
Byron, DeKalb, Crete, Elgin, Ottawa, Watseka, Algonquin, La
Salle, Lombard, Coal City, Yorkville, Dwight, Morris, Minooka,
Wilmington, Hammond, Aurora, Kentland, DeMotte, Streator, Joliet,
Rochelle, Morocco, Fowler, Belvidere, Oswego, Bradley, Fairbury,
Bolingbrook, Bourbonnais, Plainfield, Channahon, Manhattan,
Beecher, Marseilles, Naperville, Oregon, Merrillville, Gibson
City, Rensselaer, Mendota, Woodstock, Rockford, and Mundelein
906 AM CDT Tue Jun 30 2026 /1006 AM EDT Tue Jun 30 2026/

...EXTREME HEAT WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CDT /1 AM
EDT/ THURSDAY NIGHT...

* WHAT...Dangerously hot conditions with heat index values around
  105 expected each afternoon.

* WHERE...Portions of central, east central, north central, and
  northeast Illinois and northwest Indiana.

* WHEN...Until midnight CDT /1 AM EDT/ Thursday Night.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat and high humidity events.

* ADDITIONAL DETAILS...Dangerous heat is now expected to persist
  through Thursday. Thunderstorms may begin to bring some relief
  from the heat for portions of northern Illinois by Thursday
  afternoon or evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.

&&

$$

ILZ103>105-010015-
/O.CON.KLOT.XH.W.0001.000000T0000Z-260703T0500Z/
Northern Cook-Central Cook-Southern Cook-
Including the cities of Cicero, Palatine, Oak Lawn, Orland Park,
Evanston, La Grange, Chicago, Lemont, Calumet City, Oak Forest,
Oak Park, Des Plaines, Schaumburg, Park Forest, and Northbrook
906 AM CDT Tue Jun 30 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CDT
THURSDAY NIGHT...

* WHAT...Dangerously hot conditions with heat index values around
  105 expected each afternoon.

* WHERE...Central Cook, Northern Cook, and Southern Cook Counties.

* WHEN...Until midnight CDT Thursday Night.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat and high humidity events.

* ADDITIONAL DETAILS...Dangerous heat is now expected to persist
  through Thursday. Thunderstorms may begin to bring some relief
  from the heat by Thursday afternoon or evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

The magnitude of anticipated heat, combined with oppressive warmth
at night will lead to hazardous conditions, particularly for the
elderly and those with pre-existing health conditions. Residents of
the city of Chicago can call 3 1 1 to request well being checks for
elderly friends or family members, or for information on finding the
nearest cooling center.

Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.

&&

$$

Birk