The best season for touring in Tibet is from April to early November (various routes have their own golden times). The average temperature ranges from 55-75 degrees Fahrenheit and the skies are fairly clear and blue. From April to the beginning of October is the best time for treks and seeing Mount Kailash and Manasoravar Lake.
February and March – The weather is cold, dry and snowy. The Tibetan New year falls in February and it is considered to be a politically sensitive time. So, Tibet Travel Permits are not issued for at least six weeks.
Actually it is suitable to visit Tibet all year around because you can visit different regions in different seasons. Such as you can explore Nyingchi in spring, visit Mount Everest in summer, discover Lhasa in winter. In comparison, autumn is the season for most destinations in Tibet. You are suggested visit Tibet during April to October when you can get best landscape and enjoy a comfortable weather. The golden time for traveling to Tibet is August and September.
Note: Tibet tour is not available from late February to the end of March due to several big holidays held in this period of time.