January is the coldest month in China. Large parts of China are at the peak of severe winter weather, except locations in South China such as Guangzhou, Hong Kong, Macau, and Shenzhen, which do not have real winter weather.
Snow falls frequently in North China, e.g. in Harbin, Beijing, Tianjin, and usually accumulates to the thickest by the end of the month. There is still not a lot of snow as North China is dry.
Although temperatures are higher than in North China, winter in Central China and the Yangtze River Delta is bone-chilling, and feels even colder because of the humidity.
South China and Yunnan Province generally have pleasant winter with plentiful sunshine, but high altitude areas in northern Yunnan Province are frigid.
Check out The Best 6 Places to Visit in January.
North: Warm clothes such as overcoats, long underwear and fleeces are recommended.
Central: The temperature is around 0°C (32°F). A down jacket and a wind-proof jacket are needed.
South: It is warmer. Long sleeves and pants, and a wind-proof jacket are recommended. Thermals are often worn indoors on the coldest days, as there is usually no central heating in the South.
It is extremely cold in North China, cold and damp across Central China, and parts of southern China too.
Harbin is recommended for its Ice and Snow Festival, and nearby ski resorts. Harbin has one of China's best ski resorts, Yabuli Ski Resort.
Ski resorts have grown rapidly in recent years around Beijing, partly in response to the increasingly large expat community in the city. Today there are more than 10 ski resorts. See Ski Resorts in Beijing.
Hainan Island is well-known to Chinese tourists, and it is beginning to be known by foreign holiday makers for its sunny beaches and pleasant winter. For winter travelers, Hainan is not unlike Hawaii for US citizens; it serves as a tropical oasis to escape the frozen winter. See Beaches in Hainan.
Guangzhou, Hong Kong, Macau, and Shenzhen, located in Southeast China, have warm/mild winters.
Wintering in Yunnan Province in Southwest China is generally pleasant, except for mountainous areas. Kunming, the Spring City, and the tropical rainforest of Xishuangbanna, are recommended.