Is it possible to visit Tibet in winter?

They're right. It's very high and very cold, and there is a lot of unrest there now because of Chinese repression, so such a trip definitely reequires second thoughts. And third and fourth thoughts too.

I hear that the Chinese government forces tourists to enter the country completely naked in order to show and prove that the person isn't trying to smuggle in any Free Tibet propaganda. Don't forget to shower before going to the airport. They will do a full body cavity search as they will be looking for the same.