The National Weather Service has issued a heat advisory that will be in effect through 7 p.m. Friday.
High temperatures are expected to reach the low to mid-90s on Thursday and upper 90s on Friday. The heat index is expected to be at least 100 for Thursday and Friday.
Lower temperatures will reach the mid-70s on Thursday night, the weather service said.
There could be an increase in heat-related illnesses, and the heat can be most stressful on small children, seniors or those with medical conditions, the weather service said.
"Leaving a child or a pet in an enclosed vehicle, even for a short time, can be deadly," the weather service said in its advisory.
There also could be rolling power outages and buckling pavement, according to the National Weather Service.
Cooling stations have been set up at several locations throughout McHenry County, including:
• Ganek Municipal Center, 220 Harnish Dr., Algonquin
• Illinois Health and Human Services Building, 512 Clay St., Woodstock
• Centegra Hospital - Woodstock, 3701 Doty Road, Woodstock
• Centegra Specialty Hospital, 527 W. South St., Woodstock
• Centegra Hospital - McHenry, 4201 Medical Center Dr., McHenry
• Centegra Health Bridge Fitness Center, 200 Congress Parkway, Crystal Lake
• Centegra Health Bridge Fitness Center, 10450 Algonquin Road, Huntley
• Lake County Department of Human Services, 3235 W. Belvidere Road, Park City
– Northwest Herald