Chicago Public Schools have canceled classes on Friday due to an Extreme Cold Warning, with dangerously low temperatures expected, marking some of the coldest conditions since the 2019 polar vortex. Many other school districts in the Chicago area and across northern Illinois and southeast Wisconsin have also announced closures or shifted to e-learning as safety concerns rise. Businesses and various services are also closing in response to the severe cold forecast. With wind chills potentially dropping as low as 45 degrees below zero, authorities emphasize the importance of staying indoors and taking precautions.