A long time ago, the ancient Chinese created (创造) the 24 solar terms to guide crop planting. Each part starts with a solar term. One of the solar terms is called"Lidong" or the"Start of Winter". It means the winter is coming.
The"Start of Winter" is the nineteenth of the 24 solar terms in the traditional Chinese calendar. It is a transition between autumn and winter. After that day, most areas in China will experience a change from cool to cold weather. As the weather slowly cools down and the temperature (温度) falls, water starts freezing. Some fields freeze over. People can't see many big birds, but they can find big clams(蚌) on the beach. Ancient people believed clams came from the missing birds.
On the day of the"Start of Winter", in ancient times, Chinese people ate jiaozi to celebrate. And now eating jiaozi on this day is a must for people in North China. After the"Start of Winter", taking part in sports activities like skating becomes popular.
As an old saying goes, "On the day of the'Start of Winter', water cools suddenly(突然地)." But some winter swimming lovers will swim in the cold rivers on that day to welcome the season.