How the Lunar Calendar Works
A lunar day is the period from one moonrise to the next. Since the Moon rises about 50 minutes later each day, a lunar day is longer than a solar day, and the boundaries between them shift daily.
The first lunar day begins at the moment of the new moon and is almost always shorter than the others, sometimes only a few minutes. Therefore, a month can have 29 or 30 lunar days, and the calendar does not align with calendar dates.
- •Synodic month 29.53 days
- •A lunar day is approximately 50 minutes longer than a solar day.
- •The first lunar day is counted from the new moon and can be very short.