Summer Solstice (Xiazhi, 夏至) falls around 21 June at solar longitude 90°, the longest day in the Northern Hemisphere, traditionally marked with noodles.
Solar longitude
90°
Type
Principal term (zhongqi)
Season
Summer
Order
No. 10 of 24
Usual dates
Jun 21
Meaning and Astronomy
Xiazhi (夏至) begins when the sun reaches ecliptic longitude 90°, usually around 21 June and occasionally on the 20th or 22nd. The sun is directly over the Tropic of Cancer at about 23.4° north, giving the Northern Hemisphere its longest day and shortest night, with longer days the farther north one goes. It is a zhongqi (中氣) or principal term in the fifth lunar month.
The solstice was one of the earliest terms to be fixed: ancient astronomers measured the noon shadow with a gnomon, and the day of the shortest shadow was the summer solstice. Zhi means 'extreme'. Afterwards days begin to shorten, but because land and sea keep storing heat, the hottest weather usually comes about a month later. Taiwan has Tropic of Cancer markers in Chiayi and Hualien, where around noon on the solstice an upright pole casts almost no shadow.
The Three Pentads
First pentad: Deer shed their antlers (鹿角解) - deer were considered yang creatures, and as the first yin returns at the solstice their antlers fall.
Second pentad: Cicadas begin to sing (蜩始鳴).
Third pentad: Pinellia grows (半夏生) - this medicinal herb, whose name means 'half summer', appears in midsummer.
Climate and Farming
The plum rains peak between the Yangtze and Huai rivers, bringing concentrated rainfall and flood risk. Southern China is hot and wet with increasing typhoons; Taiwan's plum rains have mostly ended, giving hot days with afternoon thunderstorms; Hong Kong is hot and humid. Northern China has a hot spell before its rainy season.
Crops grow rapidly, but so do weeds and pests, and a cotton growers' proverb warns that weeds at the solstice are 'worse than a snake bite'. Another, 'it is not hot until the solstice has passed' (夏至不過不熱), notes the real heat is still to come. The 'three periods of dog days' (三伏) are counted from the solstice, beginning on the third geng day after it.
Customs
Ancient rulers worshipped Heaven at the winter solstice and Earth at the summer solstice; Ming and Qing emperors performed the summer rite at the Altar of Earth in Beijing, today's Ditan Park. In northern China the saying 'dumplings at the winter solstice, noodles at the summer solstice' holds, since new wheat has just come in; cold noodles and zhajiang noodles are typical. Tang-dynasty writings mention exchanging fans and cosmetic powders as summer gifts at this time.
In Guangdong and Guangxi the solstice coincides with the lychee season, and many people enjoy the fruit then. Visitors gather at the Tropic of Cancer marker in Chiayi, Taiwan, to watch the noon shadow disappear. Hong Kong and Macau have no particular solstice rituals, while midsummer festivals in northern Europe show how widely this moment is celebrated.
Seasonal Food and Wellness
The traditional idea that 'one yin is born at the solstice' leads to advice not to overindulge in cold: enjoy iced drinks in moderation and avoid setting air conditioning too low. Late nights and early mornings with a midday rest suit the long days. Light meals, plenty of fluids, mung bean soup, winter melon and tomatoes are typical, and lychees are traditionally eaten in moderation, as too many are thought to be 'heating'. These are traditional ideas, not medical advice.