u/Annual_Ad_8175

I want to travel to China in the last two weeks of December until January. I want to visit Peking, Chongquing, Shanghai, Shenzen and some natural parks along the way (e.g. Avatar mountains). I read that Peking will be quite cold. Does anyone have experience for the places and can tell me if this trip will be worth it at this time of year of if I should reschedule for another season? Thank you!