Hi Mary,
You do know it will be cold, especially at night. Layers, a good warm jacket and gloves are essential. While we didn't bring boots with us, we bought the Kiwi water proof spray at Wal-Mart and did our shoes a few days before leaving. The best thing we brought with us... Wool socks. again, got them at Wal-Mart. Having warm, dry feet makes all the difference. Be prepared for anything. We had misty days, perfectly clear blue sky days and snow days. We also had cold days, cool days and even a couple of days that were warm enough so we wore just a long sleeve shirt with no jacket at all.
We had traveled mostly in October to Austria and Bavaria, but due to work in 2010, had to go Thanksgiving week and the following week. Loved it. So much so that we did it again in 2013. Snow, lights, decorated Christmas trees everywhere, stalls selling ornaments, woodcarvings, etc., the smell of food and chestnuts cooking outside. Fires to warm up next to. Choirs singing in front of the church in Salzburg. Crowds of people enjoying the hot mulled wine and hot chocolate. The Christmas atmosphere is incredible. If these places don't put you in the holiday spirit, nothing ever could. If you like spicy, try a Bosna sandwich in Salzburg. For souvenirs, we took home the coffee mugs that the hot chocolate and wine came in. When you buy a drink, you can pay an extra 2 Euro and keep the mug, which is beautiful. You'll see. We have a collection of them, as every town and even the different markets in the same town have a unique logo or graphic on their mugs.
Paul