Oh, it is OK for you to travel to Kunming, Dali(https://www.travelchinaguide.com/cityguides/dali.htm) and Lijiang(https://www.travelchinaguide.com/cityguides/lijiang.htm) during Middle Dec. It is not too cold with a temperature of about 3~15C. Pack warm winter overcoat or down jacket for night, sweater and jacket for day. It seldom snow at the same time of usual year in these places, but you may also have chance to see snow. Anyhow, pay close attention to the weather forecast of these cities.