Bitter Cold? How about 70 F Here?

The weather news today was all about the "bitter cold" that was "gripping the nation", or at least the Northeast and Midwest.  I'd like to know what "bitter cold" is, that is, as defined by someone having lived their whole life in Minnesota, the UP of Michigan or North Dakota.

The article says Sioux Falls, SD hit 11 below zero (that's -11 F) today. That's not "bitter cold" for South Dakota.  -20 would be bitter cold there.

Oh, and here in Newport News, VA it hit 70 degrees today.  Light breeze, mostly sunny.  Fantastic day.  Tomorrow won't be so nice though.