The longer the coat the better, as it will keep you warm. Knee length or longer. Get a water repellent one in case there is a wet snow. All you have to do is brush the snow off of it. A huge, wet poncho will really be a pain every time you go inside a building, so I wouldn't recommend wearing one. Cords are warm pants to wear, and I would bring long johns too. Get the thin, silk ones. I am not a layerer, as it just too hot when you get on the trains, go in stores, museums and restaurants, so prefer a coat I can take off. Big, ski type mittens are great as they don't absorb water or snow and are super warm. If you like, wear them with some thin gloves with the finger tips cut off so your hands won't freeze when you take your mittens off to take photos. Nice warm hat that covers your ears, and if you can, try to find one that combines a knit/fleece inner part and water repellant outside covering, and a good scarf will all help to keep you warm. Shoes or boots with thick soles will keep your feet warm, the thicker the better. It does no good to wear knee high boots with a thin leather sole. Your feet will freeze. Don't wear Ugg boots either. They soak up water like a sponge and you will really regret bringing them. Plus, they have no support.