Names of the Months of the Jewish Calendar

The Jewish calendar has a leap year

Shofar Bohemia Probably 18th century Item number: 89.4.2899 at the Metropolitan Museum of Art
Shofar.Bohemia.Probably 18th century.Item number: 89.4.2899 at the Metropolitan Museum of Art. CC Flickr User unforth

The months of the Hebrew calendar are referred to mostly by number in the Bible, but they were also given names almost identical to the names for the Babylonian months. They're based on lunar cycles, not exact dates. Each month begins when the moon is just a thin crescent. The full moon occurs in the middle of the Jewish month, and the new moon, called Rosh Chodesh, occurs near the end of the month. When the moon reappears as a crescent again, a new month begins. 

This process does not take 30 or 31 days like the secular calendar, but rather 29½ days. Half days are impossible to factor into a calendar, so the Hebrew calendar is broken down into either 29 or 30 day monthly increments. 


Nissan typically covers the secular months of March into April. The most notable holiday during this time is Passover. This is a 30-day month and marks the beginning of the Jewish year. 


Iyar happens from April into May. Lag B'Omer is the major holiday. Iyar lasts 29 days. 


The third month of the Jewish calendar covers May into June, and its most significant Jewish holiday is Shavuot. It lasts for 30 days. 


Tammuz covers from mid-June into July. There are no major Jewish holidays during this period. It lasts 29 days. 

Menachem Av 

Menachem Av, also called Av, is the month of July into August. It's the month of Tisha B'Av and it lasts for 30 days.


Elul is the secular equivalent of mid to late August and it lasts into September. There is no major Hebrew holiday during this time period. Elul is 29 days' long.


Tishrei or Tishri is the seventh month of the Jewish calendar. It lasts for 30 days from September into October, and the High Holidays occur during this time, including Rosh Hashanah and Yum Kippur. This is a sacred time in the Jewish religion. 


Cheshvan, also called Marcheshvan, covers the secular months of October into November. There are no major holidays during this time period. It can be either 29 or 30 days, depending on the year. The rabbis who first began working out the Jewish calendar in the fourth century CE realized that limiting all months to either 29 or 30 days wasn't going to work. Two months were then given a bit more flexibility, and Cheshvan is one of them.


Kislev is the month of Chanukah, spanning November into December. This is the other month that is sometimes 29 days long and sometimes 30 days long. 


Tevet occurs from December into January. Chanukah ends during this period. Tevet lasts 29 days. 


Shevat takes place from January into February and it is the month of the Tu B'Shvat celebration. It lasts 30 days.


Adar wraps up the Jewish calendar ... sort of. It takes place from February into March and it marks Purim. It lasts 30 days.

Jewish Leap Years

Rabbi Hillel II is credited with realizing that a lunar month is 11 days' shy of a solar year. Were he to ignore this wrinkle, traditional Jewish holidays would eventually be celebrated at all times of the year, not in the seasons when they were intended. Hillel and other rabbis corrected this problem by adding a 13th month at the end of the year seven times in each 19-year cycle. So the third, sixth, eight, 11th, 14th, 17th and 19th years of this cycle have an extra month, which is called Adar Beit. It follows "Adar I" and lasts 29 days.