Summer Solstice

Introduction

Shortest noon shadow, longest day: high summer approaches

The Summer Solstice is the tenth solar term, beginning when the sun reaches 90° of ecliptic longitude, around 21–22 June. The sun is almost overhead at the Tropic of Cancer; the northern day is longest and the noon shadow shortest, after which days shorten. Its three pentads are deer shedding their antlers, cicadas beginning to sing, and pinellia sprouting. Heat and rain arrive together, so crops and weeds both grow fast and farmers hoe, drain and guard against drought; in the north people eat noodles on this day.

Timeline

1. 655 BCEOriginIn the Spring and Autumn period (c. 7th century BCE) the summer solstice was fixed by measuring the sun's shadow with a gnomon; the Zuozhuan for 655 BCE already lists the solstices among the moments to be recorded.
2. 239 BCEEvolutionThe Lüshi Chunqiu (Zhongxia ji, c. 239 BCE) records that 'in this month the day reaches its longest, and yin and yang contend', marking the summer solstice.
3. 104 BCEEvolutionWith the Taichu calendar of 104 BCE under Emperor Wu of Han, the twenty-four solar terms entered the official calendar, and Summer Solstice became a fixed term in it.
4. 1530ImpactIn 1530 the Ming built the Altar of Earth (Fangze altar) in Beijing, where Ming and Qing emperors sacrificed to Earth every summer solstice.

Heritage Listings

1. 2006National List of Representative Items of Intangible Cultural Heritage1st batch · X-68 Twenty-Four Solar Terms of the Lunar Calendar · nominated by the China Agricultural Museum · collective item
2. 2016UNESCO Representative List of the Intangible Cultural Heritage of HumanityThe Twenty-Four Solar Terms · knowledge in China of time and practices developed through observation of the sun's annual motion · collective inscription