The winter of Beijing is windy and dry. It is cold in December, local people will wear sweaters and cotton-padded clothes if they go outside. Especially you will visit some sightseeing spots in the daytime, you need to wear more to keep warm. The average low temperature is 18/21(F) and the average high is 36/40 (F). Do not need to worry about the hotel, it is air-conditioned. Remember to drink more water everyday.