When is autumn in September? Early autumn or mid-autumn or late autumn?

Autumn is one of the four seasons. Meteorologically, the autumn in the north temperate zone is from August 23rd (summer) to165438+1October 20th (light snow). Autumn in the south temperate zone is from February 19 (rain in the northern hemisphere) to May 2 1 (xiaoman in the northern hemisphere).

"Equinox" has two meanings:

1, and the time of day and night is equal. On this day, the sun reached the longitude of the yellow meridian 180 degrees and headed straight for the equator of the earth. Therefore, in most parts of the world, 24 hours are divided equally between day and night, 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 the day began to be shorter than the night. Near the North Pole, there are long nights and stars for six months in a year.

2. The climate changes from hot to cold. According to the division of seasons in ancient China, which started with beginning of spring, Changxia, beginning of autumn and beginning of winter, the autumnal equinox is divided into 90 days in autumn and divided equally in autumn.

Extended data:

"Twenty-four solar terms" is a knowledge system and social practice formed by China people by observing the movement of the sun for a year and understanding the changing laws of the four seasons, climate and phenology in a year. "Twenty-four solar terms" guide traditional agricultural production and daily life, and are an important part of China's traditional calendar system and related practical activities. In the field of international meteorology, this time cognition system is known as "the fifth invention of China".

20 17 Beijing design week, an important creative design exhibition and exchange platform in Asia, publicly solicited the design of the "24 solar terms" logo system for the whole world. He Zhong Meihua Education, as the organizer of the youth section, launched a collection activity for the creative design of the "Twenty-four Solar Terms" logo for primary and secondary schools across the country, leading the majority of young people to actively participate in the inheritance and practice of Chinese excellent traditional culture with design thinking in an entertaining way in the classroom.

Baidu encyclopedia-autumnal equinox

Baidu Encyclopedia-Autumn