An arctic blast will bring temperatures as low as zero to much of the nation by Wednesday.

According to the Associated Press, residents of the South and Midwest are bracing for what experts are calling a “polar vortex.”

The bone-chilling temps that lie ahead are the coldest in decades and will shatter records in some areas.

About half the country could even see below-zero temperatures, CNN notes.

Temperatures in Chicago, Indianapolis and Minneapolis will fall to 15 degrees below zero, 21-below in Madison, Wisconsin and more than 30-below in Fargo, N.D., the AP reports.

The frigid temps combined with the wind-chill will pose a serious threat to anyone outdoors, even just for few minutes. Officials in the Midwest and South where the wind-chill is expected to be dangerously low, have closed or delayed openings for schools throughout the regions.

Residents in usually-balmy Florida are also going to feel some of the chill as well. Temperatures in Northern Florida are expected to fall as low as 20 degrees overnight.