What does rain mean in the twenty-four solar terms?

The rain in the twenty-four solar terms means that the rain has begun.

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. Rainwater solar terms usually mean that rainfall begins and gradually increases. Wu Cheng's book "Twenty-four Solar Terms" in the Yuan Dynasty said: "The first month is aquatic in the sky, and spring is wood. However, people who grow trees must have water, so it rained successfully in beginning of spring. If the east wind melts, it will disperse into rain. "

In Yizhoushu, there are phenological descriptions such as "Hongyan coming" and "vegetation sprouting" after the rain. The water that nourishes the growth of all things comes from rain. As the saying goes, "Spring rain is as expensive as oil", and everything needs rain to moisten it, so people often regard spring rain as particularly precious. Many of the 24 solar terms directly reflect precipitation, which shows that China ancestors attached great importance to precipitation.

From the meteorological point of view, the highest temperature in most parts of China can generally rise above 0℃ after the rain. Although it has entered the spring rain solar term, there is no breath of spring in most parts of northern China.

The average temperature in many areas of South China is above 10℃. At this time, rape, winter wheat, etc. Generally, it will turn green, which requires higher moisture. As the saying goes, "Spring rain is as expensive as oil", and suitable precipitation is very important for the growth of crops. At this time, the precipitation in North China, Northwest China and Huanghuai areas is generally less. If there is little rain in early spring, timely irrigation after rain is beneficial to crop growth.

Because China is different, some areas are in early spring and some areas are in late spring. Snow is an important symbol of winter, and it is still snowing in some parts of northern China, and it is still very cold.

The solar term with the heaviest snow all year round in the middle and lower reaches of the Yellow River is neither "light snow and heavy snow" nor "slight cold and severe cold" (because the temperature was low at that time and there was less water vapor in the atmosphere), but the "rain" solar term in the spring of late February. The southwest and most of the south of the Yangtze River is a scene of early spring, with warm sunshine and green fields. South China is full of spring and flowers are in full bloom. Spring scenery is everywhere in southern Yunnan.