Study Sheet – Jewish Calendar

1. A Lunisolar Calendar

The Jewish calendar is lunisolar: months follow the moon (29 or 30 days) and intercalary months are added to align with the solar year.

• Regular year: 12 months (~354 days)
• Embolismic (leap) year: 13 months (~384 days) — addition of Adar II

Intercalary months (Adar II) are added seven times per 19-year cycle (Metonic cycle), ensuring that festivals fall in the correct season (Passover in spring).

The current fixed calendar was established by Hillel II in the 4th century. Previously, the Sanhedrin declared the new month based on eyewitnesses of the new moon.

Jewish days begin in the evening, based on the verse of Creation: "There was evening and there was morning — one day" (Bereshit 1:5).

The year count begins from Creation (birth of Adam, 1st of Tishrei, Year 1).

2. The Hebrew Months

Two orderings exist:

Chodesh malei: 30-day month → Rosh Chodesh = 2 days.

Chodesh chaser: 29-day month → Rosh Chodesh = 1 day.

3. Rosh Chodesh (New Month)

Rosh Chodesh marks the beginning of each Hebrew month. It is a semi-festive day:

• Partial (abbreviated) Hallel in the morning
• Musaf
• Torah reading (4 aliyot)
• Addition of Ya'aleh veYavo in the Amidah and Birkat Hamazon

Women have a particular tradition of not working on Rosh Chodesh, as a reward for not having participated in the sin of the Golden Calf.

Formerly, the Sanhedrin would declare the new month after hearing witnesses who had seen the new moon. Signal fires were lit from mountain to mountain to transmit the information to distant communities.

4. Kiddush Levanah (Sanctification of the Moon)

Recited outdoors between the 3rd and 15th day of the Hebrew month, when the moon is visible and waxing.

It is a blessing for the renewal of the moon, symbolizing hope and the renewal of Israel.

One recites "David Melekh Yisrael chai vekayam" (David King of Israel lives and endures) and jumps three times saying "as I dance before you without being able to touch you."

The moon is a symbol of Israel: it disappears and reappears, just as the Jewish people pass through exiles and are reborn.

5. Days of the Week and Shabbat

The days of the week are numbered (Yom Rishon, Yom Sheni... through Yom Shishi), culminating in Shabbat (the seventh day). Everything is organized around Shabbat: the days are counted "toward Shabbat."

6. Yom Tov, Chol HaMoed, and Shemitah

Yom Tov: a biblically mandated day of rest (a Torah-level holiday). Two main differences from Shabbat: on Yom Tov one may kindle fire from a pre-existing flame and carry objects outdoors for the sake of the festival.

Chol HaMoed: intermediate days between the first and last days of Passover and Sukkot. Certain types of work are permitted.

Shemitah: the sabbatical year for agriculture (every 7 years) during which the land in Israel is not cultivated.

7. Special Shabbatot

Shabbat Bereshit: the Shabbat following Simchat Torah, reading the first parashah (Bereshit).

Shabbat Teshuvah (Shabbat of Repentance): between Rosh Hashanah and Yom Kippur.

Shabbat Chazon: the Shabbat before Tisha B'Av, haftarah from Isaiah (vision of destruction).

Shabbat Nachamu: the Shabbat after Tisha B'Av, haftarah of consolation from Isaiah ("Nachamu nachamu ami").

The four special parashot before Passover

• Shekalim (before Rosh Chodesh Adar)
• Zachor (before Purim)
• Parah (after Purim — the Red Heifer)
• HaChodesh (before Rosh Chodesh Nisan)

Two Torah scrolls are taken out on these Shabbatot.

8. Key Dates Summary

Key Takeaways – Summary