Lunar year

a period of 12 synodic lunar months, being about 354.5 days

A lunar year (used in some calendars) of 12 synodic months (12 cycles of lunar phases) is about 354 days long. A cosmic year is the time (about 225 million years) needed for the solar system to revolve once around the centre of the Milky Way.

The moon throughout September if it is a lunar year.