Autumn Equinox (Qiufen, 秋分) falls at solar longitude 180°, when day and night are nearly equal; it was once a day for moon rites and is now a harvest festival.
Solar longitude
180°
Type
Principal term (zhongqi)
Season
Autumn
Order
No. 16 of 24
Usual dates
Sep 22–23
Meaning and Astronomy
Qiufen (秋分) begins when the sun reaches ecliptic longitude 180°, usually between 22 and 24 September. The sun stands directly over the equator, so day and night are close to equal in length across most of the world. Afterwards the sun's direct rays move into the southern hemisphere, and in the north the days keep shortening until the Winter Solstice.
Fen, 'to divide', has two senses here: day and night are divided equally, and the ninety days of autumn are split in half. Qiufen is a zhongqi (中氣) or 'principal' term, the principal term of the eighth lunar month. Together with the Spring Equinox and the two solstices, it forms one of the four cardinal points on which the calendar is built.
The Three Pentads
First pentad: Thunder ceases (雷始收聲) - thunder was thought to come from strong yang energy, which now gives way to yin.
Second pentad: Hibernating insects seal their burrows (蟄蟲坯戶) - small creatures heap up soil to close their holes before winter.
Third pentad: Waters begin to dry up (水始涸) - with less rain and continued evaporation, rivers and lakes start to fall.
Climate and Farming
After the equinox, temperatures in northern China drop faster and the far northeast may see its first frost. The Yangtze region enjoys clear autumn weather, though spells of persistent autumn rain can occur. Taiwan and Hong Kong stay warm, but the first northeast monsoon surges become more likely, bringing drier air.
This is the busiest moment of the 'three autumn tasks': harvesting, ploughing and sowing. Northern farmers bring in maize, soybeans and sorghum, then plough and sow winter wheat, as the proverb advises: 'White Dew is too early, Cold Dew too late; the Autumn Equinox is the right time to sow wheat.' In the south, late rice begins to turn golden and rapeseed is sown in some areas.
Customs
Ancient emperors performed rites to the sun at the Spring Equinox and to the moon at the Autumn Equinox; the Temple of the Moon in Beijing was used for this rite in the Ming and Qing dynasties. Over time, popular moon-viewing gathered around the Mid-Autumn Festival, which often falls close to the equinox.
Since 2018, mainland China has celebrated the equinox as the Chinese Farmers' Harvest Festival, with produce fairs and local events. The game of standing an egg on end is popular at both equinoxes, though success depends on the shell and a steady hand rather than the date.
In parts of Lingnan people gather wild greens to make 'autumn vegetable' soup. In some rural areas, plain glutinous rice balls were set on sticks at the edge of fields to 'glue the sparrows' beaks' and protect the crops - a custom with a wishful, symbolic flavour. In Japan, the equinox is a national holiday, and the surrounding week, Ohigan, is a time for visiting family graves and offering sweet rice cakes called ohagi.
Seasonal Food and Wellness
Traditional wellness thinking draws on the idea of balance between yin and yang at the equinox, favouring regular hours and food that is neither too cold nor too heating. Dryness is noticeable, and pears, persimmons, pomelo, lotus root, sesame and white fungus are common in soups and desserts.
Crabs become plump around this time, and Hong Kong, Taiwan and Jiangnan all enjoy crab season; because crab is traditionally considered cooling, it is often eaten with ginger and vinegar. These are customary habits, not health advice.