What Month Is It In The Jewish Calendar. The torah doesn’t name those months, but refers to them by number: This means that the length of jewish months are determined by the cycles of the moon.

In the jewish calendar, each month begins when the moon is just a thin crescent, called rosh chodesh, and a new moon in hebraic tradition. The jewish calendar is based on lunar cycles.1 towards the beginning of the moon’s cycle, it appears as a thin crescent.