Excessive Heat Warning, 115-Degree Heat Index For Chicago Area

ILLINOIS — The National Weather Service has issued an excessive heat warning for the Chicago area as 115 degree heat index values are expected on Wednesday.

An excessive heat warning means that "dangerous heat is happening or about to happen," the weather service said. You should avoid heavy activity and direct sunlight. Stay hydrated, find a cool place indoors, and check on children, elderly and pets, the weather service advised.

The warning is in effect from 11 a.m. to 9 p.m. on Wednesday. On Thursday, the Chicago area will be under an excessive heat watch through Thursday evening.

"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," the weather service said.

Heat index values of 115 degrees are expected on Wednesday and Thursday, according to the weather service. There may be some late afternoon lake cooling on Thursday.

Friday will still be warm with a high of 89, but turning less humid during the afternoon hours, the weather service said.