Jewish Calendar
Originally, there was no fixed calendar. There was no way to determine in advance the exact day of a coming holiday or bar mitzvah, because there was no way to determine in advance when the month would begin. Each month anew, the Sanhedrin would determine whether the month would be 29 or 30 days long—depending on when the following month’s new moon was first sighted—and would sanctify the new month.
Nowadays In the 4th century CE, the sage Hillel II foresaw the disbandment of the Sanhedrin, and understood that we would no longer be able to follow a Sanhedrin-based calendar. So Hillel and his rabbinical court established the perpetual calendar which is followed today.
According to this calendar, every month of the year, except for three, has a set number of days:
1 Nisan 30 Days Mar - Apr
2 Iyar 29 Days Apr - May
3 Sivan 30 Days May - Jun
4 Tammuz 29 Days Jun - Jul
5 Av 30 Days Jul - Aug
6 Elul 29 Days Aug - Sep
7 Tishrei 30 Days Sep - Oct
8 Heshvan 29 or 30 Days Oct - Nov
9 Kislev 29 or 30 Days Nov - Dec
10 Tevet 29 Days Dec - Jan
11 Shevat 30 Days Jan - Feb
12 Adar I (leap years only) 30 Days Feb - Mar 12
(13 in Leap Years) Adar (Adar II - leap years) 29 Days Feb - Mar
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The Jewish calendar is based on lunar cycles.1 Towards the beginning of the moon’s cycle, it appears as a thin crescent. That is the signal for a new Jewish month. The moon grows until it is full, the middle of the month, and then it begins to wane until it cannot be seen. It remains invisible for approximately two days2—and then the thin crescent reappears, and the cycle begins again.
The entire cycle takes approximately 29½ days.3 Since a month needs to consist of complete days, a month is sometimes twenty-nine days long (such a month is known as chaser, “missing”), and sometimes thirty (malei, “full”).
Knowing exactly when the month begins has always been important in Jewish practice, because the Torah schedules the Jewish festivals according to the days of the month.
The first day of the month, as well as the thirtieth day of a malei month, is called Rosh Chodesh, the “Head of the Month,” and has semi-festive status. See Why is Rosh Chodesh sometimes one day and sometimes two?
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The Hebrew (Jewish) calendar is a lunar calendar that is adjusted. It divides time according to the cycles of the moon. To understand what that means you need to become a moon watcher. Some nights the moon is full and round and on other nights it is just a tiny sliver in the night sky. This is a new moon. The time from the new moon to the full moon is a cycle.
It takes 29 or 30 days to complete a cycle. From the new moon called Hodesh in Hebrew. Hodesh is also the word for month. Twelve of these are a Shana or year.
The calendar is adjusted because a solar year is 365 days long and a moon year of 12 months is 354 days. In order to help us catch up an extra month is added on certain years, this is a leap year. Every 19 years there are seven leap years (the third, sixth, eighth, eleventh, fourteenth, seventeenth and nineteenth years). In a leap year a 13th month is added called Adar Sheni (the second Adar).
A Jewish day starts at sundown and ends at sundown. This is why holidays start "the day before" (sundown). An example of this is Yom Kippur which happens on the 10th of Tishrei - At sundown on the 9th of Tishrei the day changes to the 10th.
The Jewish week begins on Sunday (Yom Rishon - First day) and ends on Shabbat. The Jewish month begins with Rosh Hodesh.
See our Prepetual Jewish Calendarwith the Hebrew months, dates and holidays.
1 Nisan 30 Days Mar - Apr
2 Iyar 29 Days Apr - May
3 Sivan 30 Days May - Jun
4 Tammuz 29 Days Jun - Jul
5 Av 30 Days Jul - Aug
6 Elul 29 Days Aug - Sep
7 Tishrei 30 Days Sep - Oct
8 Heshvan 29 or 30 Days Oct - Nov
9 Kislev 29 or 30 Days Nov - Dec
10 Tevet 29 Days Dec - Jan
11 Shevat 30 Days Jan - Feb
12 Adar I (leap years only) 30 Days Feb - Mar 12
(13 in Leap Years) Adar (Adar II - leap years) 29 Days Feb - Mar
Jewish Holidays for 2013
Tu B'Shevat Tu B’Shevat, the 15th of Shevat on the Jewish calendar, is the day that marks the beginning of a “New Year for Trees.” Falls on Shabbat.
Purim Purim commemorates the deliverance of the Jewish people in the ancient Persian Empire from destruction in the wake of a plot by Haman, a story recorded in the Biblical Book of Esther (Megillat Esther). Work should be avoided.
Consult a Rabbi if this is not possible.
- Ta'anit Esther - February 21, 2013 The Fast of Esther
- Purim - February 24 - 26, 2013 It commemorates the salvation of the Jewish people in ancient Persia from Haman’s plot “to destroy, kill and annihilate all the Jews, young and old, infants and women, in a single day
- Shushan Purim - February 25, 2013 Purim was celebrated on a different day in Shushan than in the other cities. In all other cities, the battle against the enemies of the Jews took place on the thirteenth of Adar, and the people rested and celebrated on the fourteenth of Adar. In Shushan, however, the battle took place on the thirteenth and fourteenth of Adar, and the people rested and celebrated only on the fifteenth.
Passover Passover (Pesach) celebrates the deliverance of the Jewish people from slavery in Egypt. Our Passover megasite has tools, guides, insights, stories, inspiration—and just about everything you need to celebrate Passover (but bring your own wine). No work permitted on March 26 - 3/27/2013 and April 1 - 4/2/2013. Work is permitted only on March 28 - 3/29/2013 and March 31 with certain restrictions.
Second Passover Thirty days ago we cleaned our homes and souls of leaven, and matzahed our way through the week-long festival of Passover. And now, Pesach Sheni—a Second Passover! Work permitted
- Second Passover - April 24, 2013 During Passover there were certain persons who had become ritually impure through contact with a dead body, and could not, therefore, prepare the Passover offering on that day. They approached Moses and Aaron . . . and they said: ‘. . . Why should we be deprived, and not be able to present God’s offering in its time, amongst the children of Israel?’” (Numbers 9:6–7). In response to their plea, God established the 14th of Iyar as a “Second Passover” (Pesach Sheni) for anyone who was unable to bring the offering on its appointed time in the previous month.
Lag B'Omer The birthday of Jewish mysticism . . . Rabbi Shimon bar Yochai, who lived in the second century of the common era, was the first to publicly teach the mystical dimension of the Torah known as the “Kabbalah,” and is the author of the basic work of Kabbalah, the Zohar. On the day of his passing, Rabbi Shimon instructed his disciples to mark the date as “the day of my joy.”
- Lag B'Omer - April 28, 2013 Each Lag BaOmer, we celebrate Rabbi Shimon’s life and the revelation of the esoteric soul of Torah.
- Sefirat HaOmer - March 26 - May 14, 2013 It took seven weeks to reach the mountain. The people of Israel departed Egypt on the 15th of Nissan (the first day of Passover); on the 6th of Sivan, celebrated ever since as the festival of Shavuot, they assembled at the foot of Mount Sinai and received the Torah from God. Leviticus 23:15-16 (NIV) “‘From the day after the Sabbath, the day you brought the sheaf (omer) of the wave offering, count off seven full weeks. Count off fifty days up to the day after the seventh Sabbath, and then present an offering of new grain to the Lord." Each year, we retrace this inner journey with our “Counting of the Omer
Shavuot Shavuot marks the giving of the Torah on Mt. Sinai. The Ten Commandments are read in synagogues, just as they were in the desert on Mt. Sinai over 3,300 years ago. No work is permitted
- Shavuot - May 14 - 16, 2013 The Torah was given by God to the Jewish people on Mount Sinai. Every year on the holiday of Shavuot we renew our acceptance of God’s gift, and God “re-gives” the Torah. The word Shavuot means “weeks.” It marks the completion of the seven-week counting period between Passover and Shavuot. The giving of the Torah was a far-reaching spiritual event—one that touched the essence of the Jewish soul for all times. Our sages have compared it to a wedding between God and the Jewish people. Shavuot also means “oaths,” for on this day God swore eternal devotion to us, and we in turn pledged everlasting loyalty to Him.
Fast of the 17th of Tammuz The “Three Weeks” and Tisha B’Av are designated as a time of mourning over the destruction of the Holy Temple and the galut (exile).
- Fast of the 17th of Tammuz - June 25, 2013 The fast of the 17th of the Hebrew month of Tammuz, known as Shiva Asar B’Tammuz, is the start of a three-week mourning period for the destruction of Jerusalem and the two Holy Temples.
Fast of Tish'a B'Av The “Three Weeks” and Tisha B’Av are designated as a time of mourning over the destruction of the Holy Temple and the galut (exile). There is more to the Three Weeks than fasting and lamentation. Our sages tell us that those who mourn the destruction of Jerusalem will merit seeing it rebuilt with the coming of Moshiach.
The 15th of Av Our sages proclaimed the 15th of Av as one of the two greatest festivals of the year, yet they ordained no special observances or celebrations for it . . . Work permitted
Rosh Hashanah It is the anniversary of the creation of Adam and Eve and their first actions toward the realization of mankind's roll in God’s world: our dependence upon God as our creator and sustainer, and God’s dependence upon us as the ones who make His presence known and felt in His world.
- The Month of Elul - August 7 - September 4, 2013
- Rosh Hashanah - September 4 - 6, 2013
- Fast of Gedaliah - September 8, 2013
Yom Kippur Virtually everything you need to know about Yom Kippur, the holiest day on the Jewish calendar: How-To Guides, Essays and Insights, Prayer Service Overviews, Stories, Multimedia, and much more! Falls on Shabbat.
Sukkot Virtually everything you need to know about the holiday of Sukkot: How-To Guides, Sukkah and “Four Kinds” Wizards, Essays and Insights, Recipes, Stories, Multimedia, and much more! No work permitted on September 19 - 9/20/2013. Work is permitted on September 22 - 9/25/2013 with certain restrictions..
Shemini Atzeret & Simchat Torah Virtually everything you need to know about the holidays of Shemini Atzeret and Simchat Torah: How-To Guides, Essays and Insights, Recipes, Stories, Multimedia, and much more! No work permitted
Chanukah Chanukah commemorates the rededication of the Temple in Jerusalem after a group of Jewish warriors defeated the occupying mighty Greek armies. Work permitted, except Shabbat
Fast of Tevet 10 What happened on 10 Tevet? . . . Why do we need the Holy Temple? . . . The positive aspects of a “siege mentality” . . . The Rebbe on the Holocaust . . . Work permitted