I have never been to Hokkaido but would love to go in the winter. My wife worked there once and got sick of the snow so she is not keen on going back there. We have a temple near us and it's a nightmare around this time of year! the street near me turns to a one way system, and it takes me forever to get to anywhere
I now try to avoid it around new year. The onsens are nice though once you get past the shyness of being in a bath naked with a load of other men! Lol