Detailed information on the Rain Solar term
1. Introduction to Rain
The Rain Solar term falls around February 18th every year in the Gregorian calendar. At this time, the sun reaches 330 degrees of ecliptic longitude. , to pay for the "rain" solar term. Rain means two things. One is that the weather is getting warmer and the amount of precipitation is gradually increasing. The other is that in terms of precipitation form, there is less snow and more rain. The "Collection of the Seventy-two Hours of the Moon Order" says: "The first month of the year" In the middle, water is born in the sky. The beginning of spring belongs to wood, but what grows wood must be water, so when the east wind thaws, it will disperse and become rain. There are three periods: "In the first period, the otter sacrifices fish; in the second period, the swans come; in the third period, the vegetation starts to grow." During this solar term, the otter begins to fish, and places the fish on the shore as if he sacrifices them first and then eats them; after five days, The wild geese began to fly back from the south to the north; in five days, in the spring rain that "moistened everything silently", the grass and trees began to sprout buds as the Yang Qi rose from the ground. From then on, the earth gradually began to show a prosperous scene.
The rain solar term generally starts on February 18th or 19th and ends on March 4th or 5th.
2. Overview of solar terms
Rain means the beginning of precipitation and the amount of rainfall gradually increases. Every year around February 18, the sun reaches 330 degrees of ecliptic longitude, which is the "rain" solar term. Rain means two things. One is that the weather is getting warmer and the amount of precipitation is gradually increasing. The other is that in terms of precipitation form, there is less snow and more rain. "Collection of the Seventy-Two Hours of the Moon Order" says: "In the middle of the first month, the sky generates water. The beginning of spring belongs to wood, but what grows wood must be water, so the beginning of spring is followed by rain. And when the east wind thaws, it disperses and turns into rain. "[3] After the "rain", the temperature in most parts of China has risen to above 0℃. The average daily temperature in the Huanghuai Plain has reached about 3℃, the average temperature in Jiangnan is around 5℃, and the temperature in South China is above 10℃. The average temperature in North China is still below 0℃. Before and after rains, rapeseed and winter wheat generally grow green and have higher water requirements. "Spring rain is as precious as oil." Suitable precipitation at this time is particularly important for the growth of crops. In North China, Northwest China, and the Huanghuai region, rainfall is generally less at this time, which often cannot meet the needs of agricultural production. If there is little rain in early spring, the best economic benefits can be obtained by timely spring irrigation before and after the rain. In the area south of the Huaihe River, the main focus is to strengthen cultivating and hoeing, and at the same time clearing ditches and draining water in the fields to prevent excessive spring rains from causing root rot due to moisture. As the saying goes: "Wheat is watered with buds, and vegetables are watered with flowers." For mossed rapeseed, moss flower fertilizer should be applied in time to increase the weight of the pods. The double-crop early rice seedling cultivation in South China has begun. We should pay attention to seize the "cold tail and warm head", sow in good weather, and strive to sow all the seedlings in one go.
3. Calculation of rain date [Y*D+C]-L
Formula interpretation: multiply the last 2 digits of the year by 0.2422 plus 18.74, take the integer and subtract the number of leap years. The C value of rainwater in the 21st century is 18.73.
For example: Rain date in 2008 = [8×0.2422+18.73]-[(8-1)/4]=20-1=19, rain on February 19th.
Exception: The rain date calculated in 2026 should be reduced by one day to the 18th.
4. The origin of rain
Rain is the second solar term among the 24 solar terms. Every year around February 19, when the sun's ecliptic longitude reaches 330 degrees, it is the rain of the twenty-four solar terms. At this time, the temperature rises, the ice and snow melt, and the precipitation increases, so it is named rain. The rain solar term generally starts on February 18th or 19th and ends on March 4th or 5th. Rain, like Grain Rain, light snow, and heavy snow, is a solar term that reflects the phenomenon of precipitation.
"Collection of the Seventy-two Hours of the Moon Order": "In the middle of the first month, the sky produces water. The beginning of spring belongs to wood, but those who produce wood must have rain, so there will be rain after the beginning of spring. And the east wind has thawed. , then it disperses and becomes rain." This means that before and after the rain solar term, everything begins to sprout, and spring is coming. For example, in "Book of Yizhou", there are phenological records such as "swan geese coming" and "vegetation budding" after the Rain Festival.
5. Rain customs
During the Rain Festival, married daughters bring gifts back to their parents’ homes to visit their parents. Women who have given birth to children must bring cans of meat, chairs and other gifts to express their gratitude to their parents for their upbringing. For women who have not been pregnant for a long time, their mothers will sew a pair of red trousers for them and wear them close to their bodies. It is said that this will help them become pregnant and give birth to children as soon as possible. This custom is still popular in rural areas.
On the rainy day, there is a particularly interesting folk activity called "La Baobao". (Baobao is the godfather). The Rain Festival means godfather, which means "moistened by rain and dew, it is easy to grow".
In the past, people had the habit of praying to gods and divination for their children to see what their fortunes were and whether they needed to find a godfather. The purpose of finding a godfather is to help the son or daughter grow up smoothly and healthily. So there was the activity of La Baobao during the Rain Festival. This practice year after year has gradually become a custom.
6. Rain to maintain health
After the rain solar term, as the rainfall increases, cold and damp evils are most likely to trap the spleen. At the same time, dampness lingers and is difficult to remove, so you should focus on protecting the spleen before and after rain. During the rain solar term, the moisture in the ground gradually rises, and dew and frost appear in the morning. Therefore, in response to such climate characteristics, dietary maintenance should focus on nourishing the spleen and stomach and dispelling wind and dampness. And because the climate is cooler at this time, you can take appropriate supplements, such as honey, jujubes, yam, tremella, etc., which are all suitable for this solar term.
This kind of unpredictable weather can easily cause people's mood swings and even uneasiness, affecting people's physical and mental health, and is even more detrimental to patients with high blood pressure, heart disease, and asthma. In order to eliminate these unfavorable factors, in addition to continuing the spring mask, active mental conditioning and health exercises should be adopted. Maintaining emotional stability plays a very important role in physical and mental health.
After the rain, the spring breeze brings warmth, and disease-causing bacteria and viruses are easily spread by the wind, so infectious diseases are often prone to outbreaks in spring. Everyone should protect themselves, pay attention to physical exercise, enhance resistance, and prevent the occurrence of diseases.