Think about it. What's the difference between the wind direction in Xi 'an in winter and summer? Are there any obvious changes in precipitation in winter and summer? Why?
It is northwest wind in winter and southeast wind in summer. Affected by the monsoon, precipitation is also more in summer and less in winter. Because the summer monsoon is the wind blowing from the ocean surface, it contains a lot of water vapor and is warm and humid. The winter wind comes from the land and comes from the high pressure area in Mongolia and Siberia in winter, which is relatively cold and dry.