How many days are in a lunar cycle (synodic month)?
Quick Answer: A lunar cycle, or synodic month, lasts about 29.5 days. This is the time it takes for the Moon to go through all its phases, from new moon back to new moon.
The lunar cycle measures the period between similar phases of the Moon. When we say "synodic month," we mean the time it takes for the Moon to complete a full phase cycle as seen from Earth.
This period is slightly longer than the Moon’s orbit around Earth because the Earth itself moves around the Sun. So, the Moon has to travel a bit further to catch up and appear in the same phase again, making the cycle about 29.5 days.