Wednesday was a cold and blustery day, with high temperatures in the upper 20s and wind chills in the teens. High will remain below freezing through Sunday.
People were bundled up as they walked through downtown Hinsdale, where there is still some snow on the ground from the weekend.
"I like this time of year, it puts you in the mood for the holidays," Denise Dills said.
And if the cold puts you in the holiday mood, that that mood will likely continue up thru Christmas as cold air is here to stay.
Right now, a polar low pressure system is just to our north. Next week, a stronger, colder low dives our way - meaning even colder air. Highs will only in the teens a few days next week.
The city said for the rest of the week, people should dress in layers and wear gloves, a hat, a scarf and a warm coat.
Alicia Shaw, a crossing guard who works in Chicago's Jefferson Park neighborhood, is responsible for keeping small children safe as they make their way to Mary G Peterson Elementary School.
On cold days like Wednesday, she has to make sure she stays safe and avoids hypothermia. Initial symptoms of hypothermia include a swollen or puffy face, skin that is clod to the touch and stiff muscles.
Shaw wore four layers of clothes to keep warm while working outside. John Arnold, who sells newspapers outside the Jefferson Park CTA stop, has suffered from frostbite twice.
"About eight years ago I was at the Addison Blue Line station and it was so cold," he said, explaining that he didn't have enough layers on at the time.
Skin exposed to the frigid temperatures for long periods of time is vulnerable to frostbite. People should use their scarves to protect their faces from the wind and gloves to keep their hands warm - just like Ellis Korda, who is in the third grade at Peterson Elementary.
"I have to wear a coat because it's very cold and gloves to keep my hands warm and a hat to cover my ears," Korda said.
For anyone who needs a break from the cold, the city's warming centers are open. CLICK HERE to find one near you.
The city also asked residents to check on their elderly neighbors during the cold blast. Landlords are supposed to heat residential buildings to at least 68 degrees during the day and 66 degrees at night. Call 311 if there's a heating issue that is not being taken care of.
The deep freeze will also present some challenges for commuters. For those who rely on Metra, the tracks need to be kept clear and the trains need to keep running when temperatures dip.
Part of that plan is keeping switches free of ice and snow. There are 463 mainline switches along the Metra rail lines that need to operate properly. Some use hot air switch heaters that force hot air onto the switch. Others use gas flames or electric current to keep the switches warm. If these switches freeze up, trains can't go.
In the main yards, Metra has a cold air blower, which blasts air at 525 MPH to clear snow and ice quickly.
But even Metra admits, there can be delays on bitterly cold days. So always check for delays on bad weather days.