Why is beginning of autumn on August 7th every year?

Beginning of autumn is not always on August 7th, but between August 7th and August 9th.

In the 24 solar terms, the time of each solar term is fixed. When I say fixed, I mean the time when the sun reaches the longitude of the Yellow River, and each solar term has a degree. The specific time in beginning of autumn is the longitude of the sun's arrival 135, and this time point is beginning of autumn.

According to the Gregorian calendar, the time in beginning of autumn will only be from August 7th to 9th, because when the sun reaches longitude135th every year, it only appears on these three days. According to the China lunar calendar, the time span is relatively long. Beginning of autumn time may be in June or July of the lunar calendar.

Beginning of autumn is the 13 of the 24 solar terms. It is also the first solar term in autumn, and it is also the turning point of the prosperity of Yang and Yin. At this time, everything began to grow from lush to mature, but autumn is still in the heat period, and it has not yet come out, and sometimes it is even in the upper abdomen stage. Therefore, it is sometimes hotter in beginning of autumn, and there is a saying that "cows die of heat after autumn".

The Origin of Climate in beginning of autumn

Beginning of autumn has arrived, but not in autumn. The division of climatic seasons should be based on the "average 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 of them have not yet entered the autumn climate, and the last days of the 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".

"Autumn" means cool in summer. 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.

Beginning of autumn, July Festival. Make a word to understand spring. In autumn, things are different here.

When the cool breeze came to The Book of Rites, it was a blind wind. The bleak wind in the west is called cool wind. The temperature changed and the chill began to subside. "Zhou Yu" said that it is also true that the eyes are golden and the breeze is cold.

Wait, the Millennium falls. After the heavy rain, the cool wind came and the weather dropped. Those white beads have not yet condensed, so the white dew drips, showing the white of autumn gold.

Third class, chilling. Chilling, "Erya" said chilling, small and green; Ma Shi said that things were born in the heat and their voices changed.

In the Song Dynasty, the plane tree planted in the pot had to move into the temple. It's time to "beginning of autumn", and the master shouted, "Autumn is here." After the play, the phoenix tree dropped one or two leaves to express autumn.