depnd on when u gping lor
u go in at a full bloom winter at minus temp then u will suffer lor
like hokkidao now is damm cold
tokyo sitll ok if u got a down jacket to tank endure first
Well depends on how you are getting there. If going to Tokyo before reaching Sapporo, I would highly recommend it.
But even if you are going Sapporo straight, there are plenty of shops there. You just need something warm and windproof for the first day to go to the shops. Get one set of thermals, one sweater, a windbreaker and a warm hat to last you until you reach the shops. There are plenty of shops around the train station.