End of Heat

Introduction

The heat ends here and the autumn harvest begins

End of Heat is the fourteenth solar term, beginning when the sun reaches 150° of ecliptic longitude, around 22–24 August; chu means 'to stop', signalling that the summer heat is ending. Its three pentads are hawks laying out their prey, heaven and earth growing austere, and grain crops ripening. Wider day–night temperature ranges help crops fill quickly, and farmers use every fine day for the autumn harvest while watching for prolonged rain. Around this term falls the Zhongyuan festival, when river lanterns are floated.

Timeline

1. 139 BCEOriginThe Western Han Huainanzi (Tianwen xun, c. 139 BCE) sets out the twenty-four terms by the pointing of the Dipper's handle, recording 'fifteen days on, it points to shen: End of Heat', the earliest systematic attestation of End of Heat.
2. 104 BCEEvolutionWith the Taichu calendar of 104 BCE under Emperor Wu of Han, the twenty-four solar terms entered the official calendar, and End of Heat became a fixed term in it.
3. 1645EvolutionIn 1645 the Qing Shixian calendar replaced equal time division with the true-longitude rule, fixing End of Heat at the moment the sun reaches 150° of ecliptic longitude, as it still is today.

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