Hi, I will be in Hangzhou next week. How is the weather there and do I need to winter clothing's?

It will be cloudy and a little rainy. The average temp during next week should be about 8C. You may meet rain on 13th and 14th, so simple rainy gear is needed to be taken along.
Generally, it is a little cold, so you need wear a sweater and a thick coat. Too heavy winter clothing may be not needed.