The traditional East Asian calendars divide a year into 24 solar term

Solar term

A solar term is any of 24 points in traditional East Asian lunisolar calendars that matches a particular astronomical event or signifies some natural phenomenon. The points are spaced 15° apart along the ecliptic and are used by lunisolar calendars to stay synchronized with the seasons. Solar terms...

s (節氣). Báilù (pīnyīn

Pinyin

Pinyin is the official system to transcribe Chinese characters into the Roman alphabet in China, Malaysia, Singapore and Taiwan. It is also often used to teach Mandarin Chinese and spell Chinese names in foreign publications and used as an input method to enter Chinese characters into...

) or Hakuro (rōmaji

Romanization of Japanese

The romanization of Japanese is the application of the Latin alphabet to write the Japanese language. This method of writing is known as , less strictly romaji, literally "Roman letters", sometimes incorrectly transliterated as romanji or rōmanji. There are several different romanization systems...

) is the 15th solar term. It begins when the Sun reaches the celestial longitude of 165° and ends when it reaches the longitude of 180°. It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 165°. In the Gregorian calendar

Gregorian calendar

The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...

, it usually begins around September 7 and ends around September 23.