Undoubtedly, apart from the Arctic and the Antarctica, Tibet is one of the harshest places for human existence on our planet. It is cool in summer, but excruciatingly cold in winter. In Lhasa, the relatively humane city in Tibet, although the temperature may exceed 29 degrees Celsius (84 degrees Fahrenheit) in summer, it may plunge to minus 16 degrees Celsius (3 degrees Fahrenheit) in winter. Solar radiation is extremely strong in Tibet. The sunlight in Lhasa is so intense so that the city is also known as Sunlight City. The thin Tibetan air can neither generate warmth nor absorb heat, resulting in temperature extremes in day and night. The scenery and the wild life on the holy, snow-covered highland is very attractive although the extreme cold and thin air. April to October is the best time to visit Tibet, avoiding the coldest months from December to February. 

In northern Tibet, winter average temperature is subzero and the season lasts from October through May or June the following year. July and August are the best time to visit the area, enjoying mild temperatures, abundant sunshine, beautiful scenery and ethnic festive events. 

In eastern Tibet, bordering Sichuan Province, May, June and September are the height of the tourism season. In winter, roads are all blocked by heavy snow. Landslides are frequent occurrences, making travel quite difficult. 

Southern Tibet is balmy during May through October. Most rainfall also comes during this season between June and September. Heavy rains during the night block roads and make travel difficult. However, during this season, the scenery is at its best and there are also great festive events held. Hence, it is the preferred time to visit Lhasa, Shigatse and Nyingchi. Strong winds and cold temperatures are in November through May the following year.