Hundreds of flights have been canceled Wednesday nationwide - including in Chicago and Denver - due to bad weather, airport officials said.

Airlines have reported 400 cancellations - out of 1,700 flights daily - at Denver International Airport due to a storm that is forecast to dump seven inches of snow in the area, the airport said at 2:50 p.m. (4:50 p.m. ET). The announcement came before the heavy snow had arrived.

Delays at the Denver airport are averaging just over two hours and 15 minutes, according to the Federal Aviation Administration.

At O'Hare International Airport in Chicago, meanwhile, more than 300 flights have been canceled due to bad weather.

The Chicago Department of Aviation reported the cancellations at 3:30 p.m. (4:30 p.m. ET), as well as the fact that delays for flights that were still on - both in and out of the busy airport - averaged one hour or more.

Airlines reported delays of 30 minutes or more at Midway, another Chicago airport, the city department said.