Summer Solstice

Meaning

The Summer Solstice, Xiazhi, is the tenth of the twenty-four solar terms: the Sun at 90°, about 21 June, as far north as it goes. Zhì means the utmost: the day is the longest of the year in the northern hemisphere, and at noon the gnomon’s shadow is the shortest.

The tradition reads it as the height of yang, and so the moment yin is born: from now on the nights lengthen again, slowly, while the heat goes on rising for weeks. In the Chinese year the solstice is the middle of summer, not its start, as the winter one is the middle of winter. It is a principal term, the middle of the Horse month, and it names the fifth lunar month.

Its three pentads are the deer shedding their antlers, the cicadas beginning to sing, and the half-summer herb, pinellia, coming up, a plant whose very name, bànxià, marks the halfway point of the season.

In practice

• In BaZi nothing turns at the solstice: the month pillar stays the Horse month’s until Xiaoshu. A birth near it is no nearer a change of pillar.
• In the Chinese calendar it names the fifth lunar month, and the hottest weeks, the sānfú, are counted from it, starting on the third Geng day after the solstice, by the day’s stem.
• The Calendar marks it on its day, with the Sun at 0° Cancer, as the middle of the Horse month; astrology marks the same instant as the Sun’s entry into Cancer.
• In the zodiac and Feng Shui the month animal and the month’s star are those of the Horse month, from Mangzhong to Xiaoshu.

Across traditions

• In Western astrology the Sun enters Cancer at this very moment, the start of summer in Western reckoning.
• In Europe Midsummer and the bonfires of Saint John’s Eve keep the solstice, and the stones of Stonehenge are aligned on its sunrise.
• In Japan, Korea and Vietnam the term is geshi, haji and hạ chí; in northern China a saying pairs the two solstices with their food, dumplings at the winter one and noodles at the summer one.

Origin and history

The solstices were the first points of the Chinese year to be measured. The Zhoubi Suanjing, the Gnomon of the Zhou, gives the length of the noon shadow of an eight-foot gnomon at each solstice, and the astronomers of every dynasty measured it again: Guo Shoujing, for the Shoushi calendar of 1281, built a gnomon forty feet high at Dengfeng to time the solstices more finely than ever before.

The day was a rite of state. Under the Ming and the Qing the emperor offered the summer solstice sacrifice to Earth at the square altar north of Beijing, as he offered the winter one to Heaven at the round altar in the south. Song officials, records say, had days of rest at the summer solstice, and in many villages it was the day to taste the new wheat.

How Ulune calculates it

Ulune takes the Summer Solstice as the instant the Sun’s apparent longitude reaches 90°, 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 fell on 21 June at 08:24 UT.

Correspondences