China has a continental climate, and latitude spanning nearly 50 degrees. Much of the landmass is situated in the temperate zone, with the tropical and subtropical zones to the south, and reaching the Frigid Zone in the north, so temperatures differ strikingly across the country. 

AVERAGE WEATHER AND CLIMATE IN CHINA

China is a country with wide-ranging climatic conditions, so a decision about the best time to visit should be based on the regions you plan to tour and the kind of weather you enjoy. Autumn is normally the most comfortable season of the year (September to early October). During that period, temperatures are reasonable throughout China (about 10 till 22 degrees celcius, 50-72 degrees Fahrenheit) with a limited amount of rain. Spring roughly has the same average temperatures as autumn.

Summer (from June to the end of August) can be extremely hot with temperatures well above 25 degrees. Summer is also a rainy season in China. Winter can be incredibly cold especially in the north.

Please have a look at this website to find out more about China's weather and Climate

https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine-in-China