What is the difference between beginning of autumn and the autumnal equinox?

Beginning of autumn and the autumnal equinox are two different solar terms.

1, different times

Beginning of autumn time is: the sun reaches 135 degrees from August 6th to 9th every year.

Beginning of autumn is the13rd solar term among the 24 solar terms in the lunar calendar, and it is also the first solar term in autumn, which marks the official start of the Meng and autumn seasons: "Autumn" means that summer is cool. When we arrived in beginning of autumn, the phoenix tree began to shed its leaves, so there is an idiom "Autumn is known by falling leaves". Literally, the word "autumn" consists of "valley" and "fire", indicating the maturity of five grains. Autumn is the transitional season when the weather turns from hot to cold, and then from cold to cold.

The time of the autumnal equinox is: the sun reaches 180 degrees from September 22 to 24 every year.

The autumnal equinox is the16th solar term in the twenty-four solar terms of the lunar calendar, usually from September 22nd to 24th every year. The climate in the south began to decline from this solar term. First, on this day, the sun reached the longitude of the Yellow River 180 degrees, and directly hit the equator of the earth. Therefore, in most parts of the earth, 24 hours are divided equally, each being 12 hours.

2. The characteristics of solar terms are different

Climatic characteristics of solar terms in beginning of autumn

Beginning of autumn has arrived, but not in autumn. The division of climatic seasons should be based on the "average climate temperature", that is, the local average temperature is below 22℃ for five consecutive days, which is the real autumn. China is a vast country. Although the climate varies from place to place, most areas have not yet entered the autumn climate, and the last days of dog days are still the third day after beginning of autumn.

Especially in the south of China, this solar term is still a hot summer. At the same time, because the typhoon and rainy season are about to pass and the temperature is even hotter, TCM calls the period from beginning of autumn to the autumnal equinox "long summer". Qiu Lai's earliest Heilongjiang and northern Xinjiang will also fall in mid-August. Generally speaking, the autumn wind in the capital Beijing begins to cool down in early September, and the autumn around Qinhuai begins in mid-September.

Climatic characteristics of solar terms in autumnal equinox

After the autumnal equinox, the direct sunlight moved to the southern hemisphere, and the northern hemisphere got less and less solar radiation, but the ground lost more heat and the temperature dropped significantly. The autumnal equinox is exactly half of the 90-day journey from autumn to the first frost.

From the day of the autumnal equinox, the climate has three main characteristics: the position of direct sunlight continues to move from the equator to the southern hemisphere, and the phenomenon of short days and long nights in the northern hemisphere will become more and more obvious. The days will gradually shorten and the nights will gradually lengthen (until the winter solstice reaches the longest night and the shortest day); The temperature difference between day and night will gradually increase, and the amplitude will be higher than 10℃. The temperature drops day by day, getting colder every day, and gradually entering the late autumn season. The situation in the southern hemisphere is just the opposite.

Extended data:

In ancient China, beginning of autumn was divided into three periods: "A cool breeze blows gently; Second, wait for the white deer to be born; Third-class chilling. " Cool wind: People will feel cool when there is wind. The wind at this time is different from the hot air in summer. White dew falls: The earth will be foggy in the morning. Cicada chirping: Cicada chirping in autumn is also chirping.

According to the standard of dividing seasons according to the average climate temperature, it must be that the average temperature is lower than 22℃ for five consecutive days before autumn is considered. According to this standard, the Jianghuai area generally enters autumn in the middle and late September. After beginning of autumn, although the summer heat is hard to disappear for a while, although there is the afterglow of "autumn tiger", the general trend is that the weather is getting colder and colder. The daily temperature range is gradually obvious, which is often very hot during the day and very cold at night. In addition, the meaning of autumn also means that the crops are about to mature.

In fact, according to the standard of climatic division of seasons, the beginning of autumn is when the average daily temperature drops below 22℃ in the second half of the year. There are few areas in China where "beginning of autumn" falls in autumn, except the summer-free areas where winter and spring and autumn are connected all the year round.

References:

Baidu Encyclopedia-beginning of autumn? Baidu encyclopedia-autumnal equinox