The most important solar term among the 24 solar terms.

China divides the four seasons into 24 solar terms, namely: beginning of spring, rain, fright, vernal equinox, Qingming, Grain Rain, Long Summer, Xiaoman, Mangzhong, Summer Solstice, Slight Summer, Great Summer, beginning of autumn, Early Summer, Millennium, Autumn Equinox, Cold Dew, Early Frost, beginning of winter, Light Snow, Winter Solstice, Slight Cold and Severe Cold.

Beginning of spring is the first of the 24 solar terms, which means a new meaning of "beginning" and represents warmth and growth. Beginning of spring is the beginning of all things and the meaning of all self-renewal, which means that a new cycle has begun; Rain is the second of the 24 solar terms. Like Grain Rain, Xiaoman, light snow and heavy snow, they are all solar terms reflecting precipitation and festivals in ancient farming culture. Sting reflects the phenomenon that natural creatures germinate and grow under the influence of rhythm changes. Spring thunder suddenly, rain increased, and everything began to glow. In ancient times, the Sting Festival was also the beginning of spring ploughing. As the last solar term in spring, the vernal equinox is also an important solar term. At the vernal equinox, except the Qinghai-Tibet Plateau, Northeast China, Northwest China and North China, the rest of China has entered a beautiful spring. At this time, the climate is mild, the rain is abundant and the sun is shining, which is very suitable for the growth of crops; Qingming heralds the official start of spring.

Long summer is the first solar term in summer. At this time, sunshine increases, the temperature rises gradually, thunderstorms increase, and crops enter a vigorous growth stage, which is an important solar term for the growth of everything. Mango seeds are also called "busy planting", so the temperature rises significantly, the rainfall is abundant and the air humidity is high, which is suitable for planting cereal crops such as late rice. Therefore, in ancient times, farming was bounded by the solar term "mango"; Summer solstice is not only one of the 24 solar terms, but also a festival in the ancient folk "four seasons and eight festivals". The custom of offering sacrifices to gods and ancestors in summer solstice has a long history; As the beginning of the summer heat, the faint summer heat is very beneficial to the growth of crops, although the sun is a bit fierce, muggy and rainy. The summer heat is the hottest solar term in a year. Although the climate is hot, thunderstorms and typhoons are very frequent. At this time, the sun is fierce and humid, which is most conducive to the growth of crops, so the crops at this time are the fastest growing in a year.

Beginning of autumn is the first solar term in autumn. Entering this season means that rainfall, storms and humidity begin to decrease, and everything in nature begins to mature from lush. In summer, it is "going out of summer", which means leaving in the heat. At this point, the hot weather has come to an end and began to transition from hot to cool; Millennium is an important festival reflecting the temperature change in nature, and it is a turning point from sultry to cool in autumn. The autumnal equinox is the most balanced time between day and night in a year, and it is also the traditional Mid-Autumn Festival. As the fifth solar term in autumn, cold dew is a solar term reflecting the characteristics of climate change. The ancients always regarded cold dew as the beginning of cold. The first frost is the transition from autumn to winter. It is characterized by cold weather in the morning and evening, hot weather at noon, large temperature difference between day and night, and obvious autumn dryness.

Beginning of winter is a transition from autumn to winter, and everything is closed in winter. Naturally, it is a season to enjoy a bumper harvest and recuperate. The solstice in winter is a traditional folk festival in China. There is an ancient saying that the solstice in winter is as big as a year, so the ancients called it "off-year" or "off-year". Slight cold is the fifth solar term in winter, which indicates the change of temperature and marks the official start of season and winter. Great cold is the last of the 24 solar terms, and it is also the coldest season in a year.