The FAA halted arrivals at O’Hare again shortly before 10 a.m. but did not list a reason on its website.
The National Weather Service told The Associated Press that “dense, freezing fog” developed overnight throughout the city and its surrounding suburbs, leading to travel difficulties. The weather service reported visibility at Chicago’s airports was less than a quarter of a mile in some spots.
“These are just about the worst conditions you can have for flying,” weather service meteorologist Kevin Donofrio told The Associated Press. “When visibility gets down to a quarter-mile, that’s when it gets really dangerous for planes to land.”
By midmorning, nearly 50 flights had been canceled at O’Hare, and more than 70 flights canceled at Midway, split evenly between arrivals and departures, according to the Chicago Department of Aviation.
Arrivals at O’Hare were delayed by an average of about 40 minutes, while arrivals at Midway were delayed by less than 15 minutes. Departures at O’Hare had been held back by an average of 28 minutes, and at Midway, departures were running with delays of under 15 minutes.
The Associated Press contributed to this report.