金光明經文句記 6.42

6.42

四、釋隨時消息，二：初、依俗法；二、依佛法。夏之後分、冬之初分，隨俗名秋，隨此兩間消息斟酌。

Fourth, explaining the adjustment according to the season, which has two parts: first, relying on secular methods; second, relying on Buddhist methods. The latter portion of summer and the initial portion of winter are conventionally called autumn, and one adjusts and considers according to this interval between them.