What are the 24 solar terms?

People are very familiar with the 24 solar terms, especially farmers, who can not only recite them, but also use them flexibly to effectively guide agricultural production activities.

Twenty-four solar terms were invented by ancient astronomers and working people in China in agricultural production practice, which in turn served farmers' cultivation, sowing and harvest. Therefore, the calculation and prediction of the twenty-four solar terms has always been an indispensable part of the China lunar calendar.

According to ancient records, as early as the Spring and Autumn Period and the Warring States Period, China had used earth gauges (that is, poles standing upright on the ground) to measure the length of the sun shadow, and determined four solar terms: winter solstice, summer solstice, vernal equinox and autumn equinox. The basis for determination is as follows: the shortest day of noon in a year is the summer solstice; The longest shadow day at noon is the winter solstice; In the transition from summer solstice to winter solstice and from winter solstice to summer solstice, two days with moderate shadow and equal day and night are the autumnal equinox and vernal equinox. By the Qin and Han dynasties about 2 100 years ago, there were already 24 complete solar terms, which have been maintained until now. The sequential names of the 24 solar terms are: beginning of spring, Rain, Sting, Vernal Equinox, Qingming, Grain Rain, Long Summer, Xiaoman, Busy, Summer Solstice, Slight Summer, Great Summer, beginning of autumn, Early Summer, White Dew, Autumn Equinox, Cold Dew, Early Frost, beginning of winter, Light Snow, Heavy Snow, Winter Solstice, Slight Cold.

In the long years of use, people have gradually sorted out twenty-four solar terms songs that are easy to remember:

The spring rain shakes the spring and clears the valley, and the summer is full of mountains and summers.

Autumn dew, autumn frost, little snow in winter and cold in winter.

Solar terms depend on the sun

Earth, the mother of life,

That huge and broad body,

It is the place where everything lives.

But don't forget;

The fiery red sun,

Gave eternal and endless warmth;

With the quiet earth,

Also bathed in the warmth of the sun.

Yes, the sun is very important to the earth and everything on it. The 24 solar terms reflect the changes of the four seasons on the ground. As long as people look at what solar terms they are currently in, they can have a general understanding of the future climate, and the reason is also inseparable from the dominance of the sun.

Why do you know climate change when you know the solar terms? It turns out that the degree of climate change in a certain area first depends on the way the sun shines. When the sun shines vertically or nearly vertically, the ground receives more light and heat, and the climate will be hot; When the sun shines obliquely, there will be less light and heat, and the climate will be cold. Summer is coming, the position of the sun is getting higher and higher, the heat received by the ground is gradually increasing, and the heat released is also gradually increasing. When it reaches the summer solstice, it receives the most heat, but it takes about 1 month to reach the maximum, so the hottest weather does not appear in the summer solstice, but after the summer solstice about 1 month. It is no wonder that the summer solstice in the 24 solar terms is followed by a slight summer heat and a great summer heat. Summer is also hot. Similarly, the coldest time is not the winter solstice, but the winter solstice after about 1 month, so it is a great cold.

Working people in ancient China have long known that climate change is related to the position of the sun. Taking advantage of this dependence, the ancients invented watches to determine the seasons by observing the changes of the sun's shadow. The Book of the Later Han Dynasty recorded the eight-foot shadow length of each of the 24 solar terms, which was a record of the ancients setting seasons according to the length of the shadow.

Solar terms have a long history.

In ancient China, before the invention of using standard tables to determine seasons, the stars in twilight, sunrise and sunset, and the direction pointed by Beidou bucket handle were used to determine seasons. These data are recorded in China and his early almanac in the summer. "Moon Order" specially records the astrology and phenology at the beginning and middle of the month. Whenever stars and phenology appear, you will know what season it is, and you will know what crops to plant and what to do in farm work. Around the middle and late Warring States period, people divided 1 tropical year into 34 intervals according to the astrological and phenological knowledge at the beginning of the month, and gave themselves names, which is the origin of the 24 solar terms. In the Spring and Autumn Period, there was the name of the sun solstice in the south and the name of the sun solstice in the north, which may be the proper name for measuring the shadow length of the winter, summer and solstice by using the standard table. In the late Warring States period, there were eight solar terms, namely beginning of spring, Spring Equinox, Long Summer, Summer Solstice, beginning of autumn, Autumn Equinox, beginning of winter and Winter Solstice. Except for the vernal equinox and autumnal equinox, as well as the winter and summer solstice, the rest are in line with modern times. The eight solar terms are the most important of the 24 solar terms, which are separated by about 46 days. Huainanzi records all the names of the 24 solar terms, which is completely consistent with modern times. This is the earliest record of all the names of the 24 solar terms. From the unearthed documents, it can be proved that solar terms were definitely used to remember calendars in the Western Han Dynasty, so at that time, it had developed to the point where we could grasp the seasons just by reading the almanac.

Agricultural production is closely related to seasons, and the working people in ancient China have long known the importance of timely sowing. In their long-term production practice, they summed up many experiences in the relationship between seasons and farming seasons, and compiled many songs to master farming seasons and festivals, which were widely circulated among working people. When a certain season comes, people will be familiar with the time to do farm work. Twenty-four solar terms and seasonal songs compiled according to different climatic characteristics in different places have greatly helped and promoted the development of agricultural production. Although the Gregorian calendar has been used in China for several decades, the 24 solar terms are still very popular in China and still play a favorable guiding role in agricultural production.

Some people say that solar terms belong to the solar calendar, which is quite right. But it is also a unique product of the lunar calendar. The sun marks the year and the moon marks the moon, which is the characteristic of the Yin and Yang calendars used in ancient China. It is necessary to set a leap month to adjust the cold and warm seasons. Because of the leap month, the season is not very fixed in the month. For example, some phenology sometimes appears at the beginning of Dan and sometimes at the end of the month. The 24 solar terms were created to accurately show climate change. This is a pure solar calendar. Many countries in the ancient world used the lunar calendar, and only China created 24 solar terms, which can prove the wisdom of ancient working people and the development of agricultural production and science and technology in ancient China.

The meaning of solar term names

"There are many rains during the Qingming period, and pedestrians on the road want to break their souls." Du Mu's poems were famous in the Tang Dynasty. Why are the bright solar terms "rainy"?

The Yellow River is the birthplace of the Chinese nation, and the 24 solar terms also originated here. Because of its important practical value, it was quickly popularized throughout the country. But it mainly reflects the general situation of the Yellow River basin, and other areas can of course refer to it. Du Mu describes the spring rain in Jiangnan.

The meaning of the twenty-four solar terms belongs to astronomy, meteorology, phenology and crops, which basically reflects the various characteristics of a year.

Beginning of spring: It means that winter is coming to an end and spring has begun.

Rain: After beginning of spring, the weather became warmer and the rain began to increase.

Surprise: after the rain clears, there will be spring thunder roaring and hiding underground.

The hibernating creatures also wake up, so this solar term is called a fright.

Vernal equinox: The vernal equinox is divided equally between day and night, which is the middle of spring.

Qingming: After the vernal equinox, the spring is bright, the weather is fine, and everything breeds.

Grain Rain: The rain has obviously increased, and the grain is growing vigorously.

Changxia: It means that summer has begun.

Xiaoman: The seeds of summer crops such as wheat are full, but it is not time for sickle harvest.

Ear seed: wheat has awns, summer crops should be harvested when they are mature, and autumn crops should be sown as soon as possible.

Summer solstice: It was called "the northern solstice" in ancient times, which means that summer is coming. The days are getting shorter and shorter.

Slight summer heat: The weather is hot from summer to the future, which is called slight summer heat.

Summer heat: It is hotter than summer heat. Summer heat is an extremely hot season in a year, so there is a saying that "summer heat is not hot, but it is dog days".

Beginning of autumn: It means autumn has begun.

Summer: the place means termination, which means the end of summer, and then the temperature begins to drop gradually.

Millennium: The weather is getting colder and the water vapor in the air can form dew on trees and flowers, so it is called Millennium.

Equinox: Day and night are equal in length, just in the middle of the equinox.

Cold dew: The weather is colder and the dew is cold.

First frost: It's beginning to frost.

Beginning of winter: Winter is coming.

Light snow, heavy snow: at the beginning of the snow season, light snow first, and then heavy snow turned into snow.

Solstice in winter: The ancients called it "Solstice in the South", which means that the cold winter has arrived. The days are getting longer and longer.

Slight cold and severe cold: the coldest season of the year.

The cold winter has passed, and spring has returned to the earth. From the meaning of solar terms, we can know that the 24 solar terms can be divided into four categories, namely: (1) indicates the change from cold to summer: beginning of spring and vernal equinox; Long summer, summer solstice; Beginning of autumn, autumnal equinox; Beginning of winter, winter solstice, eight solar terms. (2) There are five solar terms symbolizing temperature change: slight heat, great heat, intense heat, slight cold and severe cold. (3) There are seven solar terms reflecting precipitation: rain, Grain Rain, white dew, cold dew, first frost, light snow and heavy snow. (4) About farming activities, there are four solar terms: Sting, Qingming, Xiaoman and Mangzhong.

The establishment of the twenty-four solar terms is not only a brilliant achievement in the history of science in China, but also has great practical significance in guiding agricultural production until modern times. Please read agricultural proverbs if you don't believe me!

Farming has no rules, and it all depends on solar terms.

In early spring, the sun is turning and the rain is by the river.

Frightened crows, the vernal equinox drops dry.

Qingming is busy planting millet, and Grain Rain is busy farming.

Long summer goose feathers live, birds come here.

Everyone was happy when the awn was planted, but cotton could not be found on the summer solstice.

The summer heat is not hot, but the summer heat is in the dog days.

Beginning of autumn is busy playing indigo and sharpening knives and sickles in summer.

In the Millennium, there is no land in the autumn equinox.

The cold dew is not too cold, but the first frost turns cloudy.

Land is closed in early winter, and Xiaoxue River is closed.

Snow became the moon in winter, and the winter solstice lasted for nine days.

Slight cold busy comprador, great cold New Year.

Division of solar terms

China has successfully formulated and used the lunar calendar since ancient times, so the 24 solar terms should naturally be subordinate to the lunar calendar! In fact, the 24 solar terms are purely solar calendars. Why?

When analyzing the significance and changes of the twenty-four solar terms, we can clearly find that the cycle of the twenty-four solar terms is based on the cycle of spring, summer, autumn and winter, which is a reflection of the earth's rotation around the sun. Because human beings live on the earth, they can't feel the movement of the earth, but they see the sun moving in the starry sky, which runs just once a year. We call this movement of the sun a visual movement, and the path it runs is called the ecliptic. The ecliptic is a great circle with a circumference of 360 degrees. The twenty-four solar terms are to divide the ecliptic into 24 segments, each of which is 15 degrees. Every time the sun moves 15 degrees (actually, the earth moves around the sun 15 degrees), it means 1 solar term. The time it takes the sun to complete each segment is basically the same, so the date of the 24 solar terms in the Gregorian calendar has hardly changed. For example, Tomb-Sweeping Day is around April 5th every year, and the winter solstice festival is around 65438+February 22nd every year. The dates of the 24 solar terms in the solar calendar can be summarized in two sentences, namely:

Six or two in the first half of the year;

Come eight, two and three in the second half of the year;

Only a day or two before and after.

There is a discrepancy of 1 to 2 days before and after, which is caused by the uneven speed of the sun.

The date of the twenty-four solar terms of the lunar calendar is very uncertain; Because the year of the lunar calendar is about 1 1 day less than the return date, the date of the same solar term in a certain year is about 1 1 day later than the previous year. For example, Tomb-Sweeping Day in 1978 is February 28th, while Tomb-Sweeping Day in 1979 is March 9th. The leap year is about 384 days in the lunar calendar, which is about 19 days older than the return. As a result, the solar term date of next year is about 19 days earlier. For example, the lunar calendar 1979 is a leap year, and Tomb-Sweeping Day 1980 is advanced to February 19. It can be seen that in the lunar calendar, the date of solar terms will not be known without consulting the calendar, and the date of solar terms every year will be determined through complicated calculations.

Sanfu and Jiujiu

In addition to paying attention to the solar terms most related to agricultural production, people also pay special attention to the hot and cold seasons every year. Among them, three volts and ninety-nine is a special case that has been noticed. There is a phrase in Su Dongpo's poem that "the days of 1999 are numbered", which means that 1999 is almost over. In the book "Scenery of the Imperial Capital", there is also a record of "Relief Map of Cold Region in 1999". The content is to draw 1 plum blossom, 8 1 petal, 1 sky dye 1 petal on the solstice in winter, and it will end in the ninth year.

From the date of winter solstice, there are 9 days every year; After 998 1 day, it is almost 12 March (leap year 1 1 year March), and the vernal equinox is just nine days later, so there is a saying that "999 plus 19, cattle are plowed everywhere".

The saying of "blessed day" can be traced back to the Spring and Autumn Period at the latest. "Historical Records" has the saying that "Degong fell first in the second year (676 BC)"; There is a book called Notes for Beginners in the Tang Dynasty, which makes it very clear that the third watch is the first one after the summer solstice, the fourth one is the middle, and beginning of autumn is the last one, which is called the third watch. The calculation of dog days is not as simple as 1999, but it has some changes, so people often ask such a question, that is, how to infer dog days? Why are there 20 days in some years and only 10 days in others? In fact, it is not difficult to count as a lucky day. In ancient times, there were records of branches and branches, and there were provisions in history. The third day after the summer solstice was the first fu, the fourth day was the middle fu, and the first day after beginning of autumn was the last fu. In this way, the first and last days are 10 days, while the middle days are sometimes 10 days and sometimes 20 days, depending on the trunk and branches of the summer solstice. For example, the summer solstice of 1977 is June 2 1, the main branch is its own, the 22nd is the first Geng Day, then the third Geng Day is July 12, and the main branch is Geng Wu, so this day is the beginning of the head. The fourth Geng Day is July 22nd, and the main branch is Chen Geng, which is the beginning of Zhongfu. August in early autumn? The first Geng Day after beginning of autumn is August 1 1, which is the last day, so there are 20 days in the middle of 1977.

After the winter solstice, it begins to enter the coldest season of the year, so everyone can understand that the ninth year begins from the winter solstice. It is directly related to the change of the position of the sun. As the saying goes, heat is in the middle, and cold is in the 39 th. This is based on people's practical experience. Mid-autumn and March 9 are almost all around summer and winter to more than 20 days in the future, which is consistent with the actual climate. There is a historical development process as to why the auspicious day should be decided by Gengri. The popularity of the ancient theory of five elements reflects an idea of the change of five elements. Although this idea has no scientific significance here, it has been used up to now, because its change does not exceed the range of 10 day, and it can still basically reflect the law of climate change.

Twenty-four solar terms and leap month

Ancient historians in China divided the 24 solar terms into solar terms and neutral terms, which were arranged alternately. Among them, the singular solar terms are beginning of spring, Jingzhe, Qingming, Changxia, Mangzhong, Xiaoshu, beginning of autumn, Bailu, Hanlu, beginning of winter, Daxue and Xiaohan. Even numbers are neutral gases, namely, rain, vernal equinox, Grain Rain, Xiaoman, summer solstice, great summer heat, early summer heat, autumn equinox, early frost, light snow, winter solstice and great cold.

The lunar calendar takes 12 as the symbol of1February, that is, every month has a certain amount of neutral gas, such as rain in the first month, vernal equinox in February and so on.

In ancient times, there were different arrangements for the lunar leap month, but since the Han Dynasty, a leap method has gradually formed, calling the lifeless month the leap month of the previous month. As I said just now, there is a certain amount of qi corresponding to it every month. Why is there no gas for a month? This question is not difficult to understand. Because there are twenty-four solar terms in a tropical year, it means that the average between solar terms or neutral gas and neutral gas is (365.2422÷ 12=)30.4368 days, and a lunar month is 29.5306 days, which is nearly one day apart, so the date of neutral gas (solar terms) in the middle of lunar month is backward every month. In the long run, there will always be a phenomenon that gas rushes to the end of the month, so there will be no gas next month, and there is still a solar term left. So this neutral month is called this year's leap month, and it is called the name of last month, but a leap is added before the month. For example, the date of neutral gas in the first seven months of 1979 (the lunar calendar is the last year) is: there is no neutral gas in leap June here, only one solar term-beginning of autumn.

The reason why the lunar calendar regards the month without neutrality as leap month is to do a simple operation and discover the mystery. Originally, 19 tropical year has (19× 12 =) 228 solar terms and neutral qi, and 19 lunar year has (19× 12+7=)235 long months.

In the seven-leap method of 19 years, leap months are generally arranged in 3, 5, 8, 1 1, 14, 16, 19 years, and the interval years are, for example, 3, 2 and 3. But there are other arrangements. According to this law, we can infer the general situation of leap year. For example, if the lunar calendar 1974 is a leap year, 1955,1936 ...193,2019 years ago. However, the names of leap months are not the same, so it should be calculated accurately according to the above principles.

Once in February; Three times in March; Six times in April; Five times in May; Four times in June; Three times in July; Three times in August; Once in September; Once in October; November, December and the first month do not leap once. This leap month shows April, May and June most frequently, and other months are less, but 1 1 month,1February and the first month are not leap months. What is the reason? To answer this question, we have to talk about the movement of the earth around the sun.

As we all know, the earth's orbit around the sun is a slightly flat ellipse, and the sun is not in the center of this ellipse, but in its focus, so the earth is sometimes close to the sun and sometimes far from it. The closest point to the sun is called perihelion, and the farthest point is called apohelion. The closer the earth is to perihelion, the faster it moves and the smaller it is. In this way, although the earth rotates at the same angle (15 degrees), the time it takes is different. For example, it takes more than 186 days from the vernal equinox to the autumnal equinox. Obviously, the number of days between the two periods exceeded the average mentioned above (30.4368 days). Especially from the summer solstice to the intense heat, the earth is near the perihelion, with the slowest speed, and the interval between two alignments reaches the maximum (3 1.45 days), so there are many opportunities not to include the alignment of this period and the calendar months before and after it, which is also the reason for the most frequent leap in April, May and June. It takes only 179 days for the earth to run from the autumnal equinox to the vernal equinox of the following year. During this period, except the time interval between the autumnal equinox and the first frost is 30.38 days, the others are only 29 days, so the chances of leap will naturally be less. The earth moves fastest near the winter solstice, and the interval between the two gases is small. Therefore, 1 1 month,1February and the first month always contain two kinds of gases, and sometimes even three kinds of gases in a month. For example, December of the lunar calendar (Gregorian calendar 196 1) contains three qi, and November of the year of Gengshen (Gregorian calendar 1980) also contains three qi, which is the fundamental reason why the eleventh, twelfth and first months do not leap.

A simple method for calculating solar terms

It has been introduced that there is a relatively fixed correspondence between the 24 solar terms and the solar calendar, that is, the first half comes from June 2 1 day and the second half comes from August 23, but this is extremely rough. If you want to know the date and time of each solar term every year, you must check the calendar. The exact date and time of the twenty-four solar terms are determined by complicated calculation, which is not suitable for introduction in this book. In order to meet the requirements of astronomy enthusiasts, this paper only introduces a simple method to calculate solar terms, but the calculation result of this method may have an error of several minutes or even ten minutes.

This method first needs to know the date and time of each solar term in a certain year of the Gregorian calendar, and then make a concrete calculation forward or backward on this basis.

Push back:

(1) If one year is a normal year and the second year is also a normal year, then the date and time of each solar term in the first year are added by 5: 49 to get the date and time of each solar term in the second year. It can be written as an expression:

(Ping Hou Ping) X solar terms = (Qian Ping) X solar terms +5: 49.

For example, from beginning of spring at 5: 56 on February 4th of 198 1 year (normal year), calculate the date and time of 1982 (normal year) in beginning of spring.

(1982) beginning of spring =( 198 1 year) beginning of spring +5: 49.

= 5:56+5:49 on February 4th.

= February 4th 1 1: 45

(2) If the previous year is a normal year and the second year is a leap year, the date and time of each solar term in leap year 1 and 2 months are the date and time of each solar term in the first year 1 and 2 months plus 5: 49. From March to 65438+February, 1 1 points shall be deducted from 18.

Namely: (leap after leveling) 3 ~ 65438+ February× solar terms = (before leveling) 3 ~ 65438+ February× solar terms ~ 18 hours+1 minute.

For example, the date and time of the vernal equinox 1980 (leap) can be calculated from the vernal equinox 13 on March 2 1 day.

(1980) vernal equinox =( 1979) vernal equinox-18 hours 1 1 minute.

= March 2 1,13: 22-18:11.

= 3 tablets for 20 days 19: 00 1 1.

(3) If the first year is a leap year and the second year is a flat year, the date and time of each solar term in 1 and 2 months of the flat year are leap years, and the corresponding solar term is deducted 1 1 min; From March to 65438+February, the date and time of each solar term is the corresponding solar term date of leap year, plus 5: 49. The expression can be written as:

(after leap) 1 ~ February x solar terms = (before leap) 1 ~ 2x solar terms-18 hours 1 minute.

(after leap) 3 ~ 65438+ February x solar terms = (before leap) 3 ~ 12x solar terms +5: 49.

Move forward:

(1) The method of calculating the date, time and algorithm of last year's solar terms from the average solar terms is opposite to that of next year. Namely:

(flat before flat) x solar terms = (flat after flat) x solar terms -5: 49.

(2) Calculating the solar terms of the last leap year from the average year is opposite to calculating the next average year from the leap year. Namely:

(leap before leveling) 1- February x solar terms = (after leveling) 1- February x solar terms+1 1 08 o'clock.

(Ping Qianping) 3-65438+ February X solar terms = (Houping) 3-65438+ February X solar terms -5: 49.

(3) The algorithm for calculating solar terms in leap year is opposite to that in the next leap year. Namely:

(before leap) 1 ~ February x solar terms = (after leap) 1- February x solar terms+18 hours 1 1 min.