Lìqiū (Beginning of Autumn) is the 13th solar term in the traditional Chinese calendar, occurring annually on August 7th or 8th when the sun reaches 135° of the ecliptic. The Commentary on the Seventy-Two Solar Terms explains: "The seventh month's term, 'Beginning' (立) is interpreted as in spring (Beginning of Spring). 'Autumn' (秋) signifies gathering; all things gather and withdraw at this time."
"Autumn" signifies the departure of summer heat and the arrival of coolness, marking the season's commencement. By this time, paulownia trees invariably begin shedding leaves, giving rise to the idiom "One falling leaf heralds autumn."The character "秋" (qiū) combines the radicals for grain (禾) and fire (火), signifying the ripening of crops. The Start of Autumn typically heralds the waning of summer's heat and the imminent arrival of autumn. Though residual summer warmth persists afterward—manifesting as the "autumn tiger" heatwave—the overall trend is toward progressively cooler weather. Ancient Chinese regarded this solar term as a pivotal transition between summer and autumn, consistently holding it in high esteem.
Ancient Chinese divided the Start of Autumn into three periods: "First period: Cool breezes arrive; Second period: White dew forms; Third period: Cold cicadas chirp." This describes how after the Start of Autumn, winds bring a refreshing coolness distinct from summer's heat. Subsequently, morning mist appears over the land, and the cold cicadas, sensing the autumn's yin energy, begin their song.
Records indicate that during the Song Dynasty, on the day of Liqiu, potted paulownia trees were brought into the palace halls. At the precise hour of Liqiu, the court astronomer would proclaim loudly, "Autumn has arrived." Upon this announcement, the paulownia would drop one or two leaves, symbolizing the arrival of autumn.In reality, according to climatological standards for seasonal division, autumn begins when the average daily temperature stabilizes below 22°C in the latter half of the year. Except for regions with perpetual winter or those where spring and autumn merge without summer, few areas in China actually enter autumn precisely on the day of Liqiu.