Origin of the Winter Solstice: According to the records of the Zhou Dynasty, people used the Winter Solstice to worship the sky in the suburbs, and because the first month of the Zhou calendar was November in the summer calendar, the first month in the Zhou Dynasty was equal to our present November, so there was no difference between worshipping the New Year and celebrating the Winter Solstice. It was not until Emperor Wu of the Han Dynasty adopted the summer calendar that the first month and the winter solstice were separated. Therefore, it can be said that the "Winter Festival" was celebrated only after the Han Dynasty and flourished in the Tang Dynasty.

Legend of Nu Wa's creation in the winter solstice: In Huaichuan area, there is a legend of eating jiaozi in the winter solstice. In ancient times, Nu Wa scooped up earth and made people in Shennong Mountain. In winter, it was freezing, and the clay figurines' ears squeezed by Nu Wa were frozen off one after another, so Nu Wa was very anxious. So Nu Wa sewed the clay figurine's ears one by one with a needle and thread. One day, Nu Wa sewed a clay figurine's ear, let the clay figurine bite the remaining thread with her mouth, and turned to look for scissors. When she returned to the clay figurine with scissors, a good idea was born in her mind instantly.

She tied the clay figurine's ear with a thread at one end and let the clay figurine bite tightly in her mouth at the other end, so that the clay figurine's ear would not be frozen off. Later, people were afraid of freezing their ears on the winter solstice, so they tied their ears with a thread and bit them in their mouths. After a long time, I turned biting thread into eating jiaozi, because jiaozi is very similar to the shape of an ear. The custom of eating jiaozi on the winter solstice spread in Huaichuan area and continues to this day.

The winter solstice, as an important node of the 24 solar terms in China, is the shortest day and the longest night in the area north of the equator. The winter solstice is the extreme of the sun's southbound journey, and the height of the sun in the northern hemisphere is the smallest on this day. On the winter solstice, the sun shines directly on the tropic of Capricorn, and the sun is most inclined to the northern hemisphere.

The winter solstice is the turning point of the sun's southward travel. After this day, it will go back, and the direct point of the sun will start to move northward from the tropic of Capricorn (23 26' s), and the daytime in the northern hemisphere (China is located in the northern hemisphere) will increase day by day. Around the winter solstice, the earth is located near the perihelion, and its running speed is slightly faster, which causes the time for the sun to shine directly in the southern hemisphere in a year to be about 8 days shorter than that in the northern hemisphere, so the winter in the northern hemisphere is slightly shorter than that in summer.