Ancestor worship: At the end of the year, working people get more free time to prepare for the sacrifice to the ancestors. The reason the 12th lunar month is called La Yue has a lot to do with the custom of sacrifice.
First, the worship of ancestors, called "la" (腊) in Chinese, and the sacrifice for the gods, called "la" (蜡), both frequently took place in the 12th month, which led to the traditional name of the month: la yue. Second, winter is the slack season for farmers so they have time to find things to burn in the sacrifice. The radical of "腊" represents the sacrifice of meat to one's ancestors ("月" symbolizes meat).