The Hebrew month is a unit of time used in the Hebrew calendar, which is a lunisolar calendar. Each month begins with the sighting of the new moon and typically lasts 29 or 30 days. The Hebrew calendar consists of 12 months in a common year and 13 months in a leap year, with the extra month called Adar II. The months have specific names, such as Nisan, Iyar, and Elul, each associated with various religious observances and agricultural cycles. The Hebrew calendar is significant for determining the dates of Jewish holidays, including Passover and Yom Kippur.