Rosh Chodesh Adar 1. On the biblical calendar, the month of adar is the last month of the year counting from nisan (during a leap year it is called adar ii). This year we have the good fortune to be celebrating a jewish leap.
It starts the jewish month “ rosh chodesh ” means the “head of the new [moon],” and indeed it marks the start of a new lunar month. Adar (אַדָר) is the 12th month of the hebrew year, has 29 days, and corresponds to february or march on the gregorian calendar.