These dates became the starting points of the system of 24 terms. Besides astronomical observations, the Hsia Dynasty also established the Hsia Hsiaocheng, a meteorological booklet which cryptically recorded climatic and biological phenomena.
天文上的觀察之外，在夏朝製定的「夏小正」中，還依不同的月份，記載了不同的氣象和生物活動。