The northern part of Minnesota is often affectionately referred to as the "icebox of the nation". As you can see by the above forecast high temperature map for today, they have certainly earned that distinction.
Yes, you're reading the map right: -3 for a high in Grand Rapids, -2 in Hibbing, and a balmy -5 at International Falls.
The low temperature this morning in International Falls was -26. It has since warmed to a balmy -18 as of 8am CST. Good to see that they are well on their way to that -5 high for this afternoon!