The Hebrew Calendar Months: Names and Descriptions

The attached list of Hebrew months begins with Nissan and ends in Adar Bet/Baiz. This might surprise you, since the “Jewish New Year” of Rosh Hashana falls out in Tishrei. In truth, there are two possible starting points for the Hebrew calendar: Nissan and Tishrei. The bible states that the first man was created on Rosh Hashana, so the beginning of the year should be in Tishrei. However, the Exodus from Egypt occurred in Nissan, which was when the Jews became a nation. Therefore, since the story of the Exodus took place in Nissan, most people begin counting the months from Nissan rather than Tishrei.

The Hebrew calendar months are lunar months, which means that they go according to the cycle of the moon. The moon revolves around the Earth every 29 to 30 days. Therefore, each of the Hebrew months is either 29 or 30 days long.

There is a biblical commandment to sanctify the month by declaring the new month upon seeing the “new moon.” In ancient Israel, when people saw the new moon, they would come to the Sanhedrin (ruling rabbnic body), which would declare the beginning of the new month. The message would be passed on to the rest of the country through a system of fires being lit on mountaintops. Today, people who use the Hebrew calendar go according to modern lunar calculations as to when each month begins.

Solar calendars, such as the Gregorian calendar used today, have 365 days. Because the Earth takes about 365.25 days to revolve around the sun, one day is added to the Gregorian calendar every four years.

The Hebrew calendar, however, is a lunar calendar. The lunar cycle is only about 354 days long. Therefore, an entire extra “leap month” is added periodically in order to keep the cycle in line with the solar calendar. If you look at the list of Hebrew months, you’ll see that there are two Adars. The second Adar (אדר ב) occurs every year. The first Adar (אדר א), on the other hand, is a leap month. It occurs seven out of every nineteen years, according to the Metonic cycle.

The following chart shows the Hebrew months, their English transliterations, and important days that fall out in each month. This chart is also included as an attachment.

Hebrew Name / English Transliteration / Important Days in This Month

ניסן / Nissan / Pesaḥ (Passover)

אייר / Iyar / Lag B’omer (33rd day of the Omer counting)

סיון / Sivan / Shavuot/s (Tabernacles)

תמוז / Tammuz / Shva Asar B’Tammuz (17th of Tamuz - fast day)

אב / Av / Tisha B’Av (9th of Av – fast day)

אלול / Elul / None

תשרי / Tishrei / Rosh Hashana, Yom Kippur, Succot/s

מר)חשון) / (Mar)ḥeshvan / None

כסלו / Kislev / Chanukah

טבת / Tevet/s / Asara B’Tevet/s (10th of Tevet/s – fast day)

שבט / Shvat / Tu B’Shvat (new year of trees)

אדר א / Adar Aleph (First Adar)/ None

אדר ב / Adar Bet/Baiz (Second Adar)/ Taanit/s Esther (fast of Esther) Purim Shushan Purim