Jewish Holidays Rules
You can specify holiday rules based on the Hebrew calendar.
Jewish holidays are similar in structure to Fixed Date Holidays, except that there is the additional option of choosing the month to which an Adar holiday moves in a leap year. The rule for the Jewish calendar is that holidays move from Adar to Adar II on leap years, so you should very rarely have to change the default, Adar II.
See also: Recurrence Rules Options.