Ni Hao I'm gonna solo traveller to Shanghai, Suzhou, Zhouzhuang, Hangzhou, Nanjing, Beijing, Xian,

Considering the places you want to go, I suggest you to take some thick coats as well as long sleeved clothes and thin sweaters. Beijing and Xian will be cold at that time, so you need to wear coats and sweaters. Suzhou, Hangzhou, Nanjing, Huangshan and Nanjing may not be so cold as the other two cities, but you still need the long sleeved clothes and the coats.
Hope it will help you.

i would reccomened you to wear thick rather in case of coldness