Here in Chicagoland, cold varies quite a bit. Thank Lake Michigan for that. Near the lake, it's warmer-- often, downtown Chicago temps don't get below 0 F, and on the same night, Aurora Illinois may get down to 20 below zero F at the airport there. They're farther from the lake-- by about thirty miles-- and the airport is in a depression in the general landscape there.
At that, the folk up in Minnesota think we Chicagoans are soft. Ask the folk who live in International Falls*, Minnesota, where lows of 40 below (doesn't matter whether it's C or F, they both agree at this point) and a high of 20 below zero F is expected during the winter. That's the actual thermometer reading, not the wind chill. Wind chill---- well, maybe we'd better not discuss that, the readings are beyond belief for anyone who's never experienced that.
Right now, beautiful downtown Villa Park, Illinois: 12F, clear skies. High will be 23F, low for tonight 4F. Ditto for tomorrow.
*For those of you who have ever watched Rocky and Bullwinkle: International Falls is the real town that served the purpose for the cartoon "Frostbite Falls" where our heroes call home.
Edit; add-on: Just for giggles I decided to look up Aurora, Illinois. Right now, 9F, going up to 20F today. Tonight's low predicted to be 4 below zero F. Distance from the lake and terrain make the difference, it could be ten degrees colder than that in DeKalb, Illinois tonight.