Frost's Descent (Shuangjiang, 霜降), at solar longitude 210°, is autumn's last term, when frost appears in the north and persimmons and tonics are enjoyed.
Solar longitude
210°
Type
Principal term (zhongqi)
Season
Autumn
Order
No. 18 of 24
Usual dates
Oct 23
Meaning and Astronomy
Shuangjiang (霜降) begins when the sun reaches ecliptic longitude 210°, usually around 23 or 24 October. Temperatures drop sharply, and on clear, still nights the ground loses heat quickly, so water vapour near the surface turns directly into ice crystals: frost. The ancients thought frost fell from the sky, hence the name 'frost descends', though in fact it forms where it is found.
It is the last term of autumn and a zhongqi (中氣) or 'principal' term, the principal term of the ninth lunar month. The Start of Winter follows next, so Shuangjiang marks the threshold between autumn and winter.
The Three Pentads
First pentad: Jackals make offerings of game (豺乃祭獸) - wild dogs hunt heavily and lay out their prey, which looked like a sacrifice to ancient observers and served as a store for winter.
Second pentad: Plants yellow and leaves fall (草木黃落) - foliage withers and drops in full late-autumn colour.
Third pentad: Hibernating creatures all lie still (蟄蟲咸俯) - insects and small animals retreat underground, no longer moving or eating.
Climate and Farming
By Shuangjiang the Yellow River basin usually has its first frost and the northeast has already seen snow; frost reaches the Yangtze valley somewhat later. Frost is rare on low ground in southern China. In Taiwan it appears only in the high mountains during cold surges, and in Hong Kong only occasionally on high ground such as Tai Mo Shan in strong winter cold spells. Northern Taiwan turns cooler under the northeast monsoon, while Hong Kong is dry with wide daily temperature swings.
Northern farmers hurry to harvest cabbages and radishes and tend winter wheat; in the south, late rice is harvested and rapeseed and winter vegetables are sown. A proverb says 'frost at Frost's Descent means rice rots in full granaries', a piece of folk experience linking timely frost to a good year.
Customs
Chrysanthemums are at their best, and scholars of old gathered to admire them over wine and poetry. Persimmons ripen too. A southern Fujian saying holds that eating persimmons at Frost's Descent keeps away a runny nose, and in Hsinchu, Taiwan, this is the season for drying persimmons in the strong autumn wind, when fields of orange fruit become an emblem of the season.
In southern Fujian and Taiwan, a saying claims that 'a whole year of tonics is not as good as one at Frost's Descent', so families stew mutton, duck or herbal soups. In parts of Guangdong, eating beef at this time is customary.
Historically, Ming and Qing armies held rites to their banners on Frost's Descent, reflecting the old idea that autumn's austere energy suited military matters. Various local customs to dispel bad luck around this time also survive, differing widely from place to place.
Seasonal Food and Wellness
Dryness peaks now, and seasonal foods such as persimmons, apples, pears, white radish, chestnuts and Chinese yam are traditionally favoured. A common caution is not to eat many persimmons on an empty stomach or together with large amounts of high-protein food.
Wide temperature swings call for timely layers and warmth for the neck, abdomen and feet. Tonic foods should suit one's own health; the traditional sayings are cultural lore, and anyone with a chronic condition should seek professional advice.
Frost's Descent (Shuangjiang): dates and times by year