According to a statement by the National Weather Service office in Duluth, the temperature reading of minus 56 degrees in Cotton, Minn. on the morning of Jan. 31 was the coldest temperature recorded in the lower 48 states during the entire period of cold weather last week caused by the polar vortex.

Although it missed the state record of minus 60 degrees, the extremely cold weather Jan. 26-28 caused school in Carlton County to be canceled and the suspension of mail delivery — due to extremely cold wind chill — for one day (although the post office itself was still open) on Wednesday, Ja...