Approximately 75 percent of the United States will face below-freezing temperatures this week—and some regions will suffer through record-breaking cold and “dangerous to impossible travel conditions,” CNN reports. The sub-freezing weather is expected to hit on Tuesday and last through Thursday, bringing temperatures in the Upper Midwest—the area expected to be most severely hit—down to 20 to 40 degrees below zero. With wind chill, those temperatures could feel as low as 35 to 60 degrees below zero. “Chicago will likely see its coldest readings in nearly 25 years, with lows approaching the all-time record of 27 below and a daytime high on Wednesday of around 15 below,” said CNN meteorologist Dave Hennen, who predicted that temperatures could stay below zero from mid-Tuesday to mid-Friday. Heavy snow is also expected in the region, which could create the perilous travel conditions Hennen predicted.