I wonder why it rains so much in spring. It has been raining here for seven days in a row.

Gregorian calendar every February 18 or so is a rainy solar term. At this time, the sun reaches 330 degrees of the yellow meridian, which is the solar term of "rain". Rain has two meanings, one is that the weather gets warmer and the precipitation increases gradually, and the other is that there is less snow and more rain. "Twenty-four solar terms" said: "In the first month, water is in the sky. Spring belongs to wood, but there must be water for those who grow wood, so there is rain in beginning of spring. If the east wind melts, it will disperse into rain. " After the "rain", the temperature in most parts of China rose to above 0℃, the daily average temperature in Huanghuai Plain reached about 3℃, the average temperature in Jiangnan was about 5℃, the temperature in South China was above 10℃, and the average temperature in North China was still below 0℃. Before and after rainfall, rape and winter wheat generally turn green and grow, which requires high water content. "Spring rain is as expensive as oil", so proper precipitation is particularly important for crop growth. At this time, the precipitation in North China, Northwest China and Huanghuai areas is generally less, which often cannot meet the needs of agricultural production. If there is little rain in early spring, the best economic benefit can be obtained by timely spring irrigation before and after the rain. In the area south of Huaihe River, it is mainly to strengthen intertillage and hoeing, and at the same time, do a good job in clearing ditches and draining water in the field to prevent excessive spring rain from causing wet damage and rotten roots. As the saying goes, "Water the flowers with wheat, water the flowers with vegetables", and the coated rape should be topdressing with moss fertilizer in time to compete for more pods. South China's double-cropping early rice seedling cultivation has begun, so we should pay attention to "cold tail and warm head", and strive to sow all the seedlings at once.

The rainy season is changeable, which is one of the seasons with the most cold wave processes in the whole year. This kind of hot and cold weather is very harmful to the growth of crops, forests and fruits that have sprouted and turned green and people's health. While paying attention to the cold and antifreeze work of crops, greenhouse vegetables and industrial and commercial departments, we should still pay attention to personal hygiene and health care to prevent the occurrence of epidemic diseases such as colds in late winter and early spring.

Some weather proverbs about rain are based on rain and snow to predict the later weather, such as "Rain turns cloudy with rain" and "Rain falls, cloudy turns Grain Rain". According to the cold and warm weather, there are "cold rain, warm shock" and "warm rain, cold shock" Some people also predict the weather in the later period according to the wind, such as "rain comes from the east, and it will rain in the dog days" and so on.

The weather characteristics of rain solar terms have great influence on the growth of overwintering crops. An agricultural proverb says, "Rain and dew are good crops, and Da Chun Koharu is a treasure." "Spring is getting warmer and warmer, and the rain is busy." According to the weather characteristics, the vast rural areas should carry out weeding and fertilization on the middle tillage such as Sanmai, clear ditches and bury soil moisture to prepare for drainage and waterlogging prevention.

With the arrival of rain and solar terms, snowflakes are flying, and the cold air is gradually disappearing, while the days of spring breeze, melting ice and snow, moist air, mild sunshine and drizzle are coming to us.