The Jewish calendar is based on
both solar and lunar years. The average lunar year of about 354 days is
adjusted to the solar year by the addition of a leap year and an
intercalary month. Nisan is considered the first month, although the new
year begins with Rosh Hashanah, on
the first of Tishri, which is in fact the seventh month—the calendar has
different starting points for different purposes. The year 2011 translates to the Jewish year
5771–5772. The year 2012 translates to the Jewish year
5772–5773.
Month
Number of days
Nisan (March–April)*
30
Iyar (April–May)
29
Sivan (May–June)
30
Tammuz (June–July)
29
Av (July–Aug.)
30
Elul (Aug.–Sept.)
29
Tishri (Sept.–Oct.)
30
Heshvan (Oct.–Nov.)
29
in some years
30
Kislev (Nov.–Dec.)
29
in some years
30
Tevet (Dec.–Jan.)
29
Shevat (Jan.–Feb.)
30
Adar (Feb.–March)
29
in some years
30
Adar Sheni
29
(intercalary month in leap year
only)
*The months correspond approximately to
those of the Gregorian calendar.