Due to its size and location, China has widely diverse climatic conditions, varying from bitter cold in winter to unbearable heat in summer. You should base any decision about the best time to visit China on what kind of weather you prefer and on which regions you wish to visit. Autumn and spring are usually considered the best times to come to China. In these seasons, there is a limited amount of rain and temperatures are reasonable throughout China.
The climate of north-Central China (Beijing, Xian) is comparable to that of Nebraska and Kansas, with less snow and rain in winter. Late winter and early spring feature regular dust storms and haze. In south-central China (Shanghai, Guanzhou) the climate is similar to the Gulf Coast states, through winter storms occur less often. In summer the weather is hot with high humidity and frequent rain. The winter is cooler, shorter, and the sky is often overcast with drizzle. Northeast China (Shenyang, Harbin) has weather much like Minnesota. With long, hot summers and a very cold, long winter. In Xinjiang (Urumqi, Kashgar) you will encounter severe climatic conditions often with dramatic temperature changes over the course of a day. It can get incredibly hot during the day, but normally it is much cooler at night. Winter temperatures; similarly heat up during the day but plummet at night.