The traditional East Asian calendars divide a year into 24 solar terms . Báilù or Hakuro 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, it usually begins around September 7 and ends around September 23.