And Chicagoans are bundling up as the temperatures plummet, but in what's been a rough winter, people are getting used to it.
What a difference a day makes.
"Freezing cold. I can't feel my mouth," said Lisa Dewet.
From 50 and sunny Saturday to 20s, blustery and icy Sunday, folks were bundling up to try and stay warm.
"If it's windy, it's really, really cold," said Wilma van der Draaig. "That's why I'm packed up like an Eskimo."
Along Michigan Avenue, it was most certainly the out-of-towners who were suffering the most. Like some sisters on holiday from South Africa.
"My feet are frozen. I feel like I have frostbite," Kirsty Dewet said.
And of course, there is that Bears-Packers game going on at Soldier Field. But Bears fans are a hardy bunch. At the tailgate lots earlier some proudly showed off the latest in cold-weather football fashion.
"I have this big fur coat on with a raccoon on my head," said Marc Dabaco.
"If there is one thing you need to get motivated to stand here in the cold it's playing the Packers. We got to kick their butts," Ray Ruginis said.
The National Weather Service warns that conditions could result in "frost bite and lead to hypothermia if precautions are not taken. If you must venture outdoors, make sure you wear a hat and gloves."