Why are the 24 solar terms?

Twenty-four solar terms are the original cultural heritage of working people in China, which can reflect the changes of seasons, guide agricultural activities and affect the food, clothing, housing and transportation of thousands of households. Since 2000, the main political activity center in China has been concentrated in the Yellow River Basin, and the 24 solar terms have been established on the basis of climate and phenology in this area. Due to the vast territory and changeable terrain of China, the 24 solar terms are only a reference for many regions. From the literal meaning of the twenty-four solar terms: beginning of spring, Changxia, beginning of autumn and beginning of winter-respectively represent the beginning of the four seasons. "Stand" means to start. The Gregorian calendar is generally around February 4th, May 5th, August 7th and165438+1October 7th every year. Solstice in summer and Solstice in winter-this means that summer and winter have arrived. "To" means to arrive. Summer solstice and winter solstice are generally on June 2 1 day and February 22 12 of the Gregorian calendar every year. Autumnal equinox, autumnal equinox-means that day and night are equal in length. "Divide" is equal share. These two solar terms are generally around March 20 and September 23 of the Gregorian calendar every year. Rain-indicates that the precipitation begins and the rainfall gradually increases. It rains around February 18 in Gregorian calendar every year. Sting-the sudden movement of spring thunder woke the hibernating animals in the soil. At this time, the temperature rose rapidly, and the spring thunder gradually sprouted. Every year around March 5 of the Gregorian calendar is a shock. Qingming-includes the meaning of sunny weather, fresh air, gradually warming climate and lush vegetation. The Gregorian calendar is Qingming around April 5 every year. Grain Rain —— The increase of rainfall is very beneficial to the growth of cereal crops. Grain Rain is around April 20th of the Gregorian calendar every year. Xiaoman-refers to the summer crops with full seeds, but not yet mature, just small and not yet full. Every year on May 2 1 day of the Gregorian calendar, it is full. Crops with awns, such as awn seed wheat, mature and summer sowing begins. Around June 5 every year, it is a mango. Hot in summer, hot in summer, hot in summer-hot in summer means hot. The heat is not the hottest time, but the heat is the hottest season, and the heat is the day when summer is coming to an end. They are around July 7, July 23 and August 23 of the Gregorian calendar every year. White dew-the temperature began to drop, the weather turned cold, and there was dew on the vegetation in the morning. The Millennium is around September 7 of the Gregorian calendar every year. Cold dew-the temperature drops, there is condensation in the air, and there is a chill gradually. This day is usually on June 8 10 every year. First frost-it's getting colder and colder, and it's frosting. The first frost usually occurs on the 23rd day of the Gregorian calendar 10 year 10. Light snow, heavy snow-it's starting to snow, with small and large indicating the degree of snowfall. Light snow falls on Gregorian calendar165438+1October 22nd, and heavy snow falls around 65438+February 7th. Slight cold, severe cold-the weather is getting colder and colder. Slight cold is not the coldest, but severe cold is the coldest time of the year. The Gregorian calendar 65438+1October 5th and 20th are mild and severe cold. Why are there 24 solar terms? The twenty-four solar terms are divided according to the position of the sun on the ecliptic (that is, the orbit of the earth around the sun). Depending on the sun starting from the vernal equinox (longitude zero, at this moment the sun shines vertically on the equator), every advance of 15 degrees is a solar term; After a week's operation, I returned to the vernal equinox, which is a tropical year with 360 degrees, so it is divided into 24 solar terms. The spring rain of the solar term Song Dynasty, the stormy spring, the clear valley, the hot summer, the frosty autumn, the snowy winter and the chilly winter. Twenty-four solar terms are traditional folk festivals in China. As early as the Zhou Dynasty and the Spring and Autumn Period, the summer solstice, winter solstice, vernal equinox and autumn equinox were determined by measuring the sun shadow with soil gauge. Twenty-four solar terms mean dividing a year into twenty-four equal parts and giving each equal part a name. This is the origin of twenty-four solar terms. The names and order are: beginning of spring, Rain, Sting, Vernal Equinox, Qingming, Grain Rain, Changxia, Xiaoman, Mangzhong, Summer Solstice, Xiaoxia, Daxia, beginning of autumn, Chushu, Bailu, Autumn Equinox, Cold Dew, First Frost, beginning of winter, Light Snow, Heavy Snow, Winter Solstice, Slight Cold and Severe Cold. Each solar term is about half a month apart and divided into twelve months. The beginning of the month is called the solar term, and the middle of the month is called "Zhongqi". The so-called "qi" refers to meteorology and climate. Twenty-four solar terms are closely related to season, temperature, precipitation and phenology. Beginning of spring, Changxia, beginning of autumn and beginning of winter indicate the beginning of spring, summer, autumn and winter respectively, and the vernal equinox, autumnal equinox, summer solstice and winter solstice are the turning points of the season. The five solar terms of slight summer heat, great summer heat, summer heat, slight cold and great cold are the hottest and coldest periods; White dew, cold dew and first frost indicate that there is water vapor condensation in the lower atmosphere; It also reflects the degree of temperature drop. Rain, Grain Rain, light snow and heavy snow reflect the situation and degree of precipitation; Spine, clear, small full and awn grass are the characteristics of reactant climate and crop growth. Twenty-four solar terms are the result of long-term observation, exploration and summary of astronomy, meteorology and climate by laborers in China. They are the unique great scientific and technological achievements of China laborers. They have extensive application value in agricultural activities in rural areas of China, and are generally more suitable for agricultural activities in the Yellow River Basin. Beginning of spring: Standing is the beginning. Spring is stupid. The weather is getting warmer and warmer, and the vast land will show a scene of recovery. This spring has begun. Rain: It means that the climate is getting warmer, the ice and snow are melting, and the rain is increasing gradually. Sting: In spring, everything rings in Lei Zhen, and animals that hibernate in the ground begin to be unearthed. Vernal equinox: the vernal equinox is half, which is the midpoint of 90 days in spring. It is called vernal equinox, and this day is equal to day and night. Qingming: clean and clear. The climate is warm and the vegetation begins to sprout luxuriantly. Grain Rain: "Rain gives birth to hundreds of valleys". Since this day, rainfall has increased, which is conducive to grain growth. Changxia: Since long summer, crops will grow gradually in a warm climate. Xiaoman: Full fingers are full, and the seeds of summer sowing crops such as wheat are gradually full. Miscanthus: Miscanthus is also a busy species, and crops with awns such as wheat begin to mature and harvest, which is also the busiest season for planting crops in autumn. Summer Solstice: This is the right thing to do, and the shadow of this day is so short. This day is the longest day and the shortest night in the northern hemisphere, which indicates that summer is coming and the temperature will continue to rise. Summer: summer is hot, summer is hot but not hot enough. Great summer heat: it is unbearably hot, and it is the hottest season of the year. Beginning of autumn: The summer solstice is cool, and autumn begins. Autumn means that plants are about to mature, and then the temperature drops gradually. Summer heat: indicates the end, indicating that the summer heat will soon pass, and the summer heat will end on this day, and the temperature will gradually drop in most parts of China. White dew: At this time, due to the cold at night, the water vapor near the ground condenses into white dew on plants and other objects, which means that the weather turns cold. Equinox: This is the midpoint of 90 days in autumn. On this day, day and night are equal again. After this day, the days in the northern hemisphere get shorter and the nights get longer. Cold dew: The temperature continues to drop, the night is chilly, and the dew is cold, which means that the climate will gradually change from cold to cold. Beginning of winter: Winter is the end, that is to say, the crops should be harvested after harvest. Winter begins on this day. Xiaoxue: It began to snow in the north, but the amount of snow was still very small and not many times. Heavy snow: the snow will be small to large, the snowfall and days will increase compared with light snow, and there will be snow on the ground gradually. Solstice in winter: the sun shadow is the longest. On this day, the northern hemisphere has the shortest half-day and the longest night, and it began to enter the cold weather. Slight cold: cold air accumulates for a long time, and the weather is cold, but it has not reached the extreme. Great cold: The weather is extremely cold and freezing, which is the coldest season of the year.