What are the three seasons and solar terms of rain?

There are three periods of rain, one is when water otters sacrifice fish, the other is when geese come, and the third is when plants sprout. It is said that the rainy season has come, the ice on the water surface has melted, and otters have started fishing. Otters like to kill the fish and put them on the shore in turn, just like offering sacrifices, so there is a saying that "Rex sacrifices fish". Five days after the rain, the geese began to fly back to the north from the south. In five days, plants will begin to sprout as the spirit of the sun rises underground. Since then, the earth has gradually begun to show a thriving scene.

In ancient times, five days was a cycle and a solar term was fifteen days, so it was divided into three cycles. 365 days a year (average year) is 72 days, corresponding to 24 solar terms. Each climate corresponds to a phenological phenomenon, which is called climate response. Among them, the plant climate should be germination, flowering, fruiting, etc. Animals should start vibrating, singing, mating, migrating, etc. Abiotic climate should include initial freezing, thawing and thunder.

The seventy-two changes originated very early and played a certain role in agricultural activities. Although some phenological descriptions are not so accurate and some are unscientific, they still have certain reference value for understanding the climate and its changes in ancient North China. Because the initial unit of phenology at that time was small and the actual climate and region were quite different, it was difficult to be widely used.

Rain is one of the twenty-four solar terms. There are four seasons in a year, three months in spring, summer, autumn and winter, and two solar terms in each month. Each solar term has its own unique meaning. The meaning of rain solar term is that rainfall begins and gradually increases.