The experience of staying in Beijing for four years tells you that Beijing is not cold in winter because of heating. When you go out, a set of thermal underwear, a sweater, a down jacket or a tweed coat will do. If you are afraid of the cold, just buy a thicker down jacket and tweed coat. Although the temperature in Beijing is low, it is not as wet and cold as in the south. And after all, you have been indoors for a long time, with heating and no down jacket.