Diverse Climatic Conditions
Yunnan is characterized by its low latitude and its highly complex topography. The weather is very dry in the winter when the land is under the control of continental monsoons, and the summer is comfortable as the humid air is carried in from the Indian ocean. One can experience seven different types of climate in the province, namely those of the northern tropical zone, the southern Asia tropical zone, the central Asia tropical zone, the northern Asia tropical zone, the southern temperate zone, the central temperate zone and the alpine zone.
The land of Yunnan slopes down from the north to the south. The difference between the highest and the lowest points is 6,663 meters. As is expected this creates sharp differences in temperature throughout the province. Local residents describe the province as "having four seasons on one mountain, and a different weather 10 li apart". Topographical and climatic differences, along with longer frost-free periods and more sunshine, provide Yunnan with perfect conditions for developing a widely divers agricultural industry. In ancient times, the vast region along the Hengduan Mountain range and the rivers running beside the mountains was like a huge corridor through which residents of Yunnan exchanged visits and carried out trade with people from outside the province and even outside China. These river basin areas were the cradles of Yunnan's ancient civilization, and they provided a channel to link the inland areas of China with other Asian countries and even the Africas.