After a little more investigating, I found out just how cold 19 degrees, in International Falls, MN, on September 15, really is.
Before this morning it had never been below 20 in International Falls, EVER, in the entire month of September.
If you look on a weather map of North America, you never see teens outside of the Arctic, this early.
In fact, for turds and giggles...
I mean FAR north arctic.
Noticing some other towns, Rochester - 31, Mason City, 27, all the way down to Cedar Rapids and Sioux City at 32. Just as Bastardi said, north of I-80, historic freeze.