Hi, it won't snow in Shanghai, just a little cold if you'll come in the following months. There are all sorts of hotels in Shanghai, which standard do you want? Better pick one at Shanghai Hotels, there are introduction and price information of hotels in Shanghai. And for the time you staying in Shanghai, I think it depends on how many attractions do you want to be, you can check the attraction information as well as itineraries at Shanghai Tours(https://www.travelchinaguide.com/package/shanghai.htm) That's very helpful.

Thanks mr.john for youe update.