What is leap July? How often does it happen? How to calculate

July in a row is a year with two July.

According to the perpetual calendar, under normal circumstances, the lunar calendar and the solar calendar will overlap once every 19. You can look up the perpetual calendar. Before 2000, it would overlap unless there was an accident, but it has changed since 2000. I'm not sure why. It may be because the Gregorian calendar has a running year every four years, and one day, that is, 29 days, was added in February, but it was not added in 2000, which led to the confusion of the calendar.

The lunar calendar in China was originally 19 with seven runes, that is, every 19 has seven runes, and the month of each rune is the same as that before 19, but this has changed since 2000. For example, 1987 was originally Runjun, but this year should be Runjun instead of RunJuly. However, due to the confusion of the calendar, this year has become July, and in 2025 it has become June.

Therefore, under normal circumstances, Runyue will be repeated every 19 years.