The Jewish Calendar

The Jewish calendar is based on both solar and lunar years. The average lunar year of 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 2004 translates to the Jewish year 5764–5765.

Months 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 Islamic (Hijri) Calendar

The Islamic calendar is based on the lunar year of 354 days. The number of days each month is adjusted according to the lunar cycle, beginning about two days after the new moon. The months drift backward over the seasons, beginning again on the same day every 321/2 years. The Islamic year begins on the first day of Muharram, and is counted from the year of the Hegira (anno Hegirae)—the year in which Muhammad emigrated from Mecca to Medina (A.D. 622). The year 2004 translates to A.H. 1424–1425.

Months Number
of days
Muharram 29 or 30
Safar 29 or 30
Rabi I 29 or 30
Rabi II 29 or 30
Jumada I 29 or 30
Jumada II 29 or 30
Rajab 29 or 30
Sha'ban 29 or 30
Ramadan 29 or 30
Shawwal 29 or 30
Dhu'l-Qa'dah 29 or 30
Dhu'l-Hijjah 29 or 30