What Calendar Do The Jewish Use. The jewish calendar is essential to the structure of jewish life. The present jewish calendar is lunisolar, the months being reckoned according to the moon and the years according to the sun.
The jewish calendar is primarily lunar, with each month beginning on the new moon, when the first sliver of moon becomes visible after the dark of the moon. Ever since g‑d took us out of egypt, the jewish people have been keeping track of time—and celebrating the festivals—according to the lunar calendar, which contains 12 months.