On the Chinese lunar calendar, “Autumn Equinox” is the beginning of autumn and this day is just at the middle point between “Autumn Begins” to “Hoar-Frost Falls”.It arrives on September 22 to September 23 each year when the sun reaches the celestial longitude of 180 degrees.
When the cold air southward meets the declining warm and wet air, precipitation is the result. The temperature also drops frequently.
It is a good season to enjoy sweet-scented osmanthus full blossom around Autumn Equinox. At this time, it is hot in the day and cool in the night in South China, so people have to wear light clothing when it is hot, and put on more clothes when it is getting cooler. This period is named as "Gui hua zheng" in Chinese, which means osmanthus mugginess.
Qiucai is taken back and made into soup with fish, named 'Qiutang' (autumn soup). There is a verse about the soup: 'Drink the soup to clear the liver and intestines, thus the whole family will be safe and healthy.'