Winter Solstice

Meaning

The Winter Solstice, Dongzhi, is the twenty-second of the twenty-four solar terms: the Sun at 270°, about 22 December, as far south as it goes. The night is the longest of the year in the northern hemisphere, and at noon the gnomon’s shadow is the longest.

The tradition reads it as the height of yin, and so the moment yang is reborn: from now on the days lengthen, at first by seconds, then by minutes. It is the middle of winter in the Chinese year, a principal term in the middle of the Rat month, and it anchors the lunar calendar itself: the month that holds the winter solstice is always the eleventh, and every other month is counted from it.

Its three pentads are the earthworms knotting themselves in the cold ground, the elk shedding their antlers, and the springs beginning to move under the ice, the first stir of the returning yang.

In practice

• In BaZi nothing turns at the solstice: the month pillar stays the Rat month’s until Xiaohan. A birth near it is no nearer a change of pillar.
• In the Chinese calendar it names the eleventh lunar month, the one from which the others are reckoned.
• The Calendar marks it on its day, with the Sun at 0° Capricorn, as the middle of the Rat month; astrology marks the same instant as the Sun’s entry into Capricorn.
• In the zodiac and Feng Shui the month animal and the month’s star are those of the Rat month, from Daxue to Xiaohan.

Across traditions

• In Western astrology the Sun enters Capricorn at this very moment; Christmas and the older Yule gather round the same turn of the light, and the passage tomb of Newgrange, in Ireland, lets the solstice sunrise into its chamber.
• In Japan tōji is the day for a hot bath with yuzu fruit and for pumpkin; in Korea dongji brings red bean porridge, patjuk, to the table; in Vietnam it is đông chí.
• In China a saying holds that the winter solstice is as great as the New Year: families gather for sweet rice balls, tangyuan, in the south, and dumplings in the north.

Origin and history

The winter solstice was the starting point of Chinese astronomy. The Zhoubi Suanjing gives the length of the noon shadow at the solstices, and the calendar makers of every dynasty counted their year from one winter solstice to the next; the Zhou began their civil year with its month. Guo Shoujing, for the Shoushi calendar of 1281, timed the solstices with a gnomon forty feet high, and found the length of the year to within half a minute.

It was a great festival too. Meng Yuanlao writes that Song dynasty Kaifeng prized the winter solstice above all its festivals and kept it like the New Year: even the poor put on new clothes, and families made offerings to their ancestors; the emperor offered the sacrifice to Heaven at the round altar south of the capital. The custom of “counting the nines”, nine periods of nine days from the solstice, often with a picture of a plum branch of eighty-one petals coloured one a day, follows the winter until spring.

How Ulune calculates it

Ulune takes the Winter Solstice as the instant the Sun’s apparent longitude reaches 270°, from its table of the solar terms computed with the Swiss Ephemeris for 1800 to 2200. As a principal term it changes no pillar; the Calendar shows it on the reader’s own date. In 2026 it falls on 21 December at 20:50 UT, already 22 December in China.

Correspondences