Bad weather prompts hundreds of flight cancellations Wed.

(CNN) -- Hundreds of flights were canceled Wednesday nationwide -- including in Chicago and Denver -- due to bad weather, airport officials said.

Airlines 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 averaged just over two hours and 15 minutes, according to the Federal Aviation Administration.

The city's National Weather Service forecast calls for snows continuing into Wednesday night, when temperatures should dip to as low as 15 degrees. The weather should take a marked turn for the better later in the week, with a 49-degree high and mostly sunny skies predicted for Friday.

Other parts of Colorado -- specifically northern El Paso County, including Monument and Black Forest -- were under a blizzard warning through Thursday morning. The National Weather Service forecast that communities in this area could see up to six inches of snow and winds averaging 20 to 40 mph, with gusts blowing at speeds of up to 60 mph.

At O'Hare International Airport in Chicago, meanwhile, more than 300 flights were canceled due to strong rain storms there.

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 Illinois airport -- averaged one hour or more.

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

The showers and thunderstorms hitting the region Wednesday are expected to continue into Thursday. The weather service said these storms could produce small hail and gusty winds in Chicago, in addition to heavy rains that could cause flooding.