Happy fall—and the start of the new school year. Listen to autumn from Vivaldi’s four seasons:

I feel like summer everywhere is almost the same as in both vibes and time definitions: like, it’s just suppose to be hot and fun holidays. But autumn is defined differently across various cultural, astronomical, and meteorological contexts.

In the astronomical context, autumn is defined by the position of the Earth relative to the sun—when day and night are approximately equal in length, marks the start of autumn. (Sept. 22nd).

Based on temperature, meteorologists define seasons based on the temperature cycle. Thus, meteorological autumn includes September, October, and November.

Cultural definitions of autumn can vary significantly based on local climate, traditions, and agricultural practices:

  • In Chinese culture, the concept of ‘节气’ (solar terms) is used to mark changes in the seasons. The start of autumn is traditionally marked by the solar term ‘立秋’ (the start of autumn), which falls around August 7th. This system divides the year into 24 solar terms to guide agricultural activities—normally make more sense for north of China.
  • Japanese Culture: Similar to the Chinese, the Japanese also use a lunisolar calendar that divides the year into 24 sekki, corresponding closely to the Chinese solar terms. ‘Risshū’ is the term that signifies the beginning of autumn.
  • Celtic Tradition: Historically, the Celts celebrated the beginning of autumn with the festival of Samhain, which later influenced modern Halloween celebrations. This festival, held on November 1st, marked the end of the harvest and the beginning of winter.
  • In the United States and much of Europe, autumn is often culturally associated with the start of the school year, the harvest season, and the changing colors of the leaves, typically from late September through November. Or, the voting season, perhaps.