About 310 flights have been canceled at O'Hare as of 11:45 a.m., and about 65 flights have been canceled at Midway, according to the city's Department of Aviation.
Some minor delays have also been reported at Midway, according to the department.
On Wednesday, 145 were canceled at O'Hare as of 3:30 p.m., according to the city's Department of Aviation. United Airlines said it had canceled around 80 flights from O'Hare.
More than 50 flights were canceled Wednesday at Midway, where about two dozen flights were delayed an average of 30 minutes, the department said.
The Sun-Times Media Wire contributed to this report.
