The Chicago area will get a glimpse into winter temperatures this week as a freeze warning and frost advisory go into effect overnight and into Wednesday. But even before that, some in the city saw signs of the seasons changing,

Millions in the Midwest and eastern U.S. were under freeze warnings early Wednesday morning as cold temperatures move in, according to the National Weather Service. Almost 37 million people from Kansas to as far east as New England were facing subfreezing temperatures Wednesday morning.

Parts of the Chicago area Tuesday woke up to rain, rumbles of thunder and even some hail as lake effect showers swept through much of Northeast Illinois, with more rain expected through the afternoon,

"Subfreezing temperatures as low as 24 [degrees Fahrenheit] expected" in some areas of Minnesota and North Dakota, the NWS said.

Periods of rain are streaming into Chicago area off Lake Michigan as cold air sucks heat and moisture from the relatively warm water.

CHICAGO - Chicago got off to a cold start Wednesday with some spots already freezing as of this writing. East of I-65 there are still lake-effect rain showers. Those will be ending this morning. The rest of the day will be sunny to partly cloudy and chilly with highs in the mid to upper 50s.