A heat advisory has been issued for north central and northeast Illinois through Friday evening.
Hot and humid conditions are expected to last through Friday, according to the National Weather Service. Temperature highs are expected to reach the low- to mid-90s Thursday and the mid- to upper-90s Friday. The maximum heat index will be 100 to 105 degrees Thursday and 103 to 108 Friday.
Low temperatures are expected to reach into the middle 70s Thursday night.
Several days of building heat and humidity could result in an increase in heat-related illnesses, according to the National Weather Service. Heat can be most stressful to small children, the elderly and those with medical conditions.
The National Weather Service is also sending out a reminder to not leave a child or pet in an enclosed vehicle, even for a short time, because it could be deadly.
Intense heat could also lead to rolling power blackouts and buckling road pavement.