You say 'Harbin!' we say 'Ice Festival!' (and beer)
247tickets brings you access to the largest snow and ice festival in world! Bring warm clothes, bring a hat, bring sunglasses you'll need them all to make the most of this. If you haven't been, you should go. If you've aleady been - you should go again! Not like you're going to Thailand this year anyway.
Every year this gets bigger and better - there's the forest train, snow karting, that slide where you think you're going to die. Then there's the shows and all the events which bring all this together along with ice skating, snowman making - basically everything you can possibly do with snow and ice.
Running from December to late February depending on the weather, our recommendation is head there December or January.