When are the autumnal equinox and the summer solstice? What do the autumnal equinox and the summer solstice mean respectively?

Lead: The summer solstice is the time when the sun shines directly on the Tropic of Cancer in a year. This day is the longest day and the shortest night. After this day, the sun will go back until the autumnal equinox and solar terms, and the sun will return to the equator and divide the day and night equally. The solar term from summer solstice to autumnal equinox is also the hottest period in China. So, when are the autumnal equinox and the summer solstice? Next, I will introduce you to the meaning of autumnal equinox and summer solstice, as well as the time of summer solstice and autumnal equinox.

When are the autumnal equinox and the summer solstice? What do the autumnal equinox and the summer solstice mean respectively?

When are the autumnal equinox and the summer solstice? What do the autumnal equinox and the summer solstice mean respectively?

The summer solstice is on June 20th, or 2 1, or 22nd of the Gregorian calendar every year.

The autumnal equinox is usually from September 22 to 24 of the Gregorian calendar every year.

20 18 Summer solstice time: 20 18 June 2 1 Thursday Year of the Dog, the eighth day of May.

20 18 autumnal equinox date: Sunday, September 23rd, 20 18, August of the Year of the Dog 14.

What is the summer solstice solar term?

Summer solstice is one of the 24 solar terms, which occurs on June 20th, or 2 1, or 22nd of the Gregorian calendar every year. On the day of summer solstice, the sun moves to 90 degrees of the yellow meridian (summer solstice, currently in Gemini), and the position where the sun directly hits the ground reaches the northernmost point of the year, almost directly to the Tropic of Cancer. At this time, the daylight hours in all parts of the northern hemisphere reach the longest in the whole year. For the Tropic of Cancer and its northern area, the summer solstice is also the highest day of the year at noon. During the summer solstice in Beijing, the daytime can be as long as 15 hours, and the height of the sun is as high as 73 32' at noon. On this day, the northern hemisphere received the most solar radiation, almost twice as much as the southern hemisphere.

What is the summer solstice solar term?

Astronomical experts say that the solstice in summer is the turning point of the sun. After this day, I went back. The direct sunlight point moved southward from the Tropic of Cancer, and the daylight in the northern hemisphere became shorter and shorter day by day. After the summer solstice, the Tropic of Cancer and its northern region, the midday sun altitude angle also began to decrease. At the same time, after the arrival of the summer solstice, the stars in the night sky gradually became summer stars.

Solstice is the earliest of the 24 solar terms. In the 7th century BC, the shadow of the sun was measured by civil soil gauge, thus the summer solstice was determined. According to "Zunxian Manuscript", "The sun arrives in the north, the days are long and the shadows are short, so it is called the summer solstice. At best, it is excellent. " From summer to sunrise, the sun directly reaches the northernmost point of the year, almost directly to the Tropic of Cancer (23 26' north latitude), which is the longest place in the northern hemisphere. The higher the latitude, the longer the day. For example, the daily length of Haikou in Hainan is a little more than 13 hours, Hangzhou is 14 hours, Beijing is about 15 hours, and Mohe in Heilongjiang can reach 17 hours. North of the Arctic Circle, the sun is above the horizon all day, which is the widest day in the northern hemisphere. At the same time, for the Tropic of Cancer and its north, the summer solstice is also the day with the highest sun height at noon in a year. In Beijing, the height of the sun is as high as 73 32' at noon from summer to Sunday. On this day, the northern hemisphere received the most solar radiation, almost twice as much as the southern hemisphere. At this time, the southern hemisphere is in the middle of winter.

Three stages of summer solstice

Three stages of summer solstice

In ancient China, the summer solstice was divided into three phases: "The first phase of staghorn dissolution; Second, wait for cicadas to start singing; Third-class Pinellia ternata. " Although elk and deer belong to the same family, the ancients thought they belonged to yin and yang. The deer's horn faces forward, so it belongs to Yang. On the solstice of summer, Yin Qi was born, and Yang Qi began to decline, so the front antlers began to fall off. However, the elk is cloudy, so it falls off at the corner from winter to Sunday; After the solstice of summer, the male cicada fluttered and sang because of Yin Qi's feeling; Pinellia ternata is a shade-loving herb, named after it was born in swamps or paddy fields in midsummer. It can be seen that in the hot summer, some yin-loving creatures began to appear, while positive creatures began to decline.

China folks divide 15 days from summer to the future into three "hours", usually the first three days, the middle five days and the last seven days. During this period, the temperature in most parts of China was high, the sunshine was sufficient, the crops grew rapidly, and the physiological and ecological water demand was high. At this time, the precipitation has a great influence on agricultural output, and there is a saying that "raindrops are worth tens of millions in summer solstice". In general, the precipitation in the middle and lower reaches of the Yangtze River and Huanghuai area can generally meet the requirements of crop growth. The Chronicle of Jingchu's Age says: "It rained on June 3rd, and the Tian family thought it was sweet, and the whole city congratulated each other." It can be seen that as early as 1000 years ago, people had a clear understanding of the characteristics of this rainfall.

What is the autumnal equinox solar terms

What is the autumnal equinox solar terms

The autumnal equinox, the sixteenth solar term in the twenty-four solar terms of the lunar calendar, usually falls from September 22nd to 24th in the Gregorian calendar every year. The climate in the south began to decline from this solar term. First, the sun arrived at 180 (autumnal equinox) on this day, and the sun almost directly hit the equator of the earth, and the length of day and night is equal all over the world (regardless of the refraction of sunlight by the atmosphere and the shadow in the morning). After the autumnal equinox, the direct point of the sun continues to move from the equator to the southern hemisphere, and the days in the northern hemisphere become shorter and the nights become longer, that is, the days in a day are shorter than the nights; In the southern hemisphere, the days are long and the nights are short, which means the days are longer than the nights. Therefore, the autumnal equinox is also called the landing point.

At the North Pole and South Pole, on the day of the autumn equinox, the sun is on the horizon all day. After that, as the direct point of the sun continued to move southward, a six-month polar night began near the North Pole, which gradually expanded and then narrowed. A six-month polar day began near the South Pole, which gradually expanded and then narrowed.

China's ancient book "Spring and Autumn Stories, Yin and Yang in and out" said: "The autumn equinox, Yin and Yang are also half-phase, so it is cold and hot day and night." The autumnal equinox means "half" "Equinox" has two meanings:

First, day and night are equal. On this day, the sun reached the longitude 180 degrees, and directly hit the equator of the earth. Therefore, in most parts of the world, the 24 hours a day are equally divided, each being 12 hours. After the autumnal equinox, the direct point of the sun began to enter the southern hemisphere from the equator, and the northern hemisphere began to have shorter days and longer nights, and shorter days and shorter nights in a day; Near the North Pole, there are long nights and stars for six months in a year.

Second, the climate changed from hot to cold. According to the division of seasons in ancient China, which began with beginning of spring, Changxia, beginning of autumn and beginning of winter, the autumnal equinox falls within 90 days of autumn and is divided equally in autumn.