The Han calendrical system already used the concept of the 24 solar terms, although the present names for them were fixed during the T'ang dynasty (618--907). The solar terms were tied up with the traditional Chinese calendar, which has always been lunar.
對天文曆法有深入研究的圓山天文台長蔡章獻表示，漢代曆法，已經出現了廿四節氣的區分，至於今天沿用的「冬至」、「春分」等名詞，則在唐朝之後確立。他解釋說，我國一向使用的是以月亮圓缺為準的「太陰曆」。