Tibet, due to its unique geographical characteristics, is cold in winter, cool in summer and generally dry, receiving only 450 millimeters ( 18 inches) of rain or snow. Sunlight is extremely intense. The thin air neither blocks nor holds heat, so sunshine feels warm, shadows are chilly, and temperatures can vary greatly within a day, exceeding 29 ( 84 F) in summer, and plunging below 4 ( 40 F) the same night.

Regional Characteristics and Specializations

Regional Characteristics and Specializations This high plateau is the origin for most of China's major rivers - Huang He (Yellow), Yangtze (Changjiang), as well as the Mekong, Irrawaddy, Salween and the Bramaputra. In addition the Ganges and Indus find their origins in these same Mountains.

The population concentrates in the river valleys in the south. Major crops include mountain barley supplemented by yaks and yak products and some sheep.

EASTERN TIBET A land dominated by virgin forests and mild temperatures. However the terrain is highly dissected. This is the transitional area to the Chengdu Basin and the Yunnan-Guizhou Plateau. There are many different tribal peoples here.

WESTERN TIBET - This is the area closest to Pakistan and Afghanistan. Its history and trade are more associated with these areas than with India or China. It is so distinct that it is included in the Xinjiang Military District, while the rest of Tibet is part of the Chengdu Military District. It is best-known as the site of Mount Kailas and the holy lakes of Manasarovar and Rakas Tal. The source area for all of South Asia's major rivers (Indus, Sutlej, Tsangpo Bramaputra). It is a holy area for pilgrims from India (both Hindu and Buddhist cosmology) as well as Tibet. It's esoteric image goes all the way back to the early Bon religion (animism and magic). 
Mount Kailas is considered to be the throne of Siva (Shiva), by Hindus. It is mount Sumeru for the Buddhists Main town of the area is Burang (Thaklot) about 110 km (70mi) south of the mountain itself.

The administrative center for this district (Ngari or Ali District) is Shiquanhe 250km (155mi) west of the mount itself.

NORTHERN TIBET - This is the empty area dominated by the Changtang plains which are mostly swamps and pasture lands. There is very light population here and it all is nomadic. Perhaps the best analogy to this environment is the Altiplano of Bolivia and Peru.

SOUTHERN TIBET - The south facing slopes of the Himalayas (towards Nepal, Bhutan and India) are much milder in temperature and considerably more moist. These support a number of isolated population groups and specialty crops such as tea.