The climate in Tibet is complicated and diversified. Overall, the Tibetan climate features frigid and dry air in the northwest and warm and humid in the southeast, forming climatic zones (southeast-northwest)such as the tropical, subtropical, plateau temperate, and plateau sub-frigid climatic zones.

  Thibet has a clear distinction between dry and wet days. Generally speaking, the months from October to April are a dry season while the months from May to September are a wet season. Rainfall is unevenly distributed in different places of Tibet. Annual precipitation amounts to 5,000 mm in the low-lying area in the sountheastern pan dropping to 50 mm in the northwest.

  There exists great difference in climate between southern and northern Tibet. Under the impact of warm humid air currents from the Indian Ocean, the valleys in southern Tibet enjoy warm and wet weather, with the annual average temperature being 8 degrees centigrade. The northern Tibet Plateau enjoys a continental climate, with the annual temperature staying below zero. However, the icing period extends over the bulk of the year. March-October is the ideal season for visits and June-September the best season of all. Recent years have seen huge influx of visitors to Tibet in winter.

  Tibet boasts more solar radiation that any other part of China, about 100 percent or one-third more than in plains at the same latitude. In addition, Tibet enjoys longe duration of sunshine. Both the annual average temperature and the highest temperature in Lhasa and Xigaze are 10-15 degrees Centigrade lower than in Chongqing, Wuhan and Shanghai. In the Ngari area, some 5,000 meters above sea level, the temperature in August reaches 10 degrees Centigrade or higher during the day, but falls to below zero at night.

( Source: China's Tibet Facts & Figures 2008)