Tibet is one of the harshest places for human existence. It is cool in summer, but excruciatingly cold in winter.Sunlight is extremely intense. The thin air neither blocks nor holds heat, so sunshine feel warm, shadows are chilly, and temperature can vary greatly within a day, exceeding 84°F in desert areas in summer, and plunging below 39°F the same night. The most pleasant months for tourism are from April to October.
See! Yahoo Weather