I used to live in Holland and during the winter I rode to work one evening (I was working nights for Heineken) and it was -21 degrees, only about 12 miles but man was it cold.
The worst was when I was doing my forklift licence and I had to ride about 30 miles , it was -15 , blowing a gale and sleating all day long , I was leaning the bike just to go in a straight line.
Every time I stopped I was putting my hands on the engine block to stop them from freezing off , I never felt so glad to see the end of a journey , I've covered a couple of hundred miles in one day before but that was nothing compared to those few miles in such shitty conditions , after that nothing stops me riding.