The dangerous temperatures are suspected in three deaths -- two homeless men in Joliet and a man found in his garage on Chicago's Northwest Side. Last year, 12 people died due to bitter cold in Cook County.
"We really ask the citizens of Chicago to be our eyes and ears in terms of well-being checks and call us at any time, and we will send somebody out to check on that person," said Mary Ellen Caron, Department of Family and Support Services.
Eighteen floors above Wacker Drive on top of the Crain Communication Building, crews were taking down scaffolding in wind chills below zero.
"I think today by far is the coldest morning from the last couple," said construction worker Jesse Gutierrez.
Gutierrez, 26, says it's twice as windy and twice as cold up there. Heavy layers and frequent breaks inside get him through the day.
"We're kinda used to it already. We've been doing it for so long, it's just a regular daily basis," Gutierrez said.
Bitter cold temperatures stung Tuesday morning as Chicago's commuter army made their way to work, tightly bundled, some leaving little skin exposed.
"I'm just thinking that I want to be inside, and I hope I don't blow into the river," said Kit Caldwell.
"I have lots of heavy mittens on. I have three layers of clothes, two hats, and I'm walking fast," said Janice Eisenman.
"Born and raised here, so I'm used to it. You know it's gonna happen. It's December," said Craig Wenokur.
The calendar says it's not yet officially winter, but it's a different story outside. Bitter cold temperatures descended on the Chicago area again Tuesday. The thermometer was showing single-digit temperatures in some areas, and wind chills dipped below zero. Those are hardly the best conditions to be in while waiting for a CTA train or bus.
"Long johns and about three shirts and a hoodie. I got to keep it hot. It's cold out here," said commuter Jarvis Brown.
Others dealing with the cold were just trying to ignore it.
"Look at the beautiful decorations that are out for the holiday season and just wait for the bus, not too much wind right here, so it's not too bad," said commuter Mel Kershenbaum.
On Tuesday, Chicago's warming shelters, such as the Garfield Community Center, are expected to be full as temperatures remained well below freezing. City human services department employees were busy checking up on older and at-risk residents.
Experts say this start to December is one of the coldest in four years.