All Chicago Public Schools will be closed Thursday due to the impending winter weather, officials said.
CEO Janice Jackson tweeted the update Tuesday evening.
Schools remained open Tuesday but all after-school events will be canceled, CPS said in a press release.
"Due to the cancelation, CPS intends to add an additional instructional day to the end of the school year to ensure students receive the full 178 instructional days on the district’s calendar," CPS said.
A Wind Chill Warning was issued for the entire Chicago area beginning Tuesday evening.
The warning, which will take effect at 6 p.m. Tuesday and continue through noon Thursday, predicts dangerously cold wind chills as low as -55 degrees expected.
A Wind Chill Advisory will also be in place from 4 a.m. to 6 p.m. Tuesday, with wind chills between 20 and 30 below zero.
The forecast high temperature for Wednesday in Chicago is -15 degrees. If that forecast holds true, it will mark the coldest high temperature the city has seen since Jan. 20, 1994, when the high temperature was -11 degrees.
The coldest temperature the city has ever seen was -27 degrees, which happened on Jan. 20, 1985. The forecast low for Wednesday is 22 below-zero.
A Wind Chill Warning means "the combination of very cold air and the wind will create dangerously low wind chill values," according to the National Weather Service.
Frostbite can occur quickly in these conditions, the alert warns, and even hypothermia or death is possible if precautions aren't taken, NWS said.