We will travel to Lhasa on mid Setember by train from Xining.

Well, the temperature difference at daytime and night is sharp. In general, it is sunny but rains sometimes. Yo'd better take thick coat, long sleeves shirts and other thick clothes with you. If you plan to climb Mount Qomolangma or spend a night in Namtso Lake, you should bring a down jacket. And you may bring your sun screen to combat violet ray there.