Leap month

A leap month is an extra month added to some lunar or lunisolar calendars periodically to keep the calendar aligned with the Earth's orbit around the Sun. Since lunar months are about 29.5 days, a year of 12 lunar months is about 354 days—short of the solar year of approximately 365 days. To synchronize the calendar with the seasons, an additional month is inserted—called a leap month—typically every two or three years. This adjustment helps ensure that festivals and agricultural timings stay consistent with the solar year, maintaining an accurate measurement of time across seasons.