Traditional Culture Encyclopedia - Almanac inquiry - Why is there no leap month in 18 13?

Why is there no leap month in 18 13?

It's cancelled.

Emperor Jiaqing simply interfered with the Gregorian calendar artificially. After observing the comet, Qin canceled 18 13 leap in August and changed to 18 14 leap in February.

A leap month is a way to set a leap day in a calendar. The position of the lunar leap month is completely artificial from ancient times to the present, and the position of the leap month is different in different calendars of past dynasties.