The Hebrew Calendar: Cycle of Sacred Time

The Hebrew Calendar: Cycle of Sacred Time

The Hebrew calendar (לוח השנה, luach hashanah) is the system by which Judaism organizes sacred time. It is a lunisolar calendar: months are based on the lunar cycle but are adjusted to the solar year through the periodic intercalation of an additional month.

The Months of the Hebrew Year

The Hebrew year has 12 or 13 lunar months:

1. Nissan (ניסן) — spring, Passover.
2. Iyar (אייר) — connection between Passover and Shavuot.
3. Sivan (סיוון) — Shavuot, giving of the Torah.
4. Tammuz (תמוז) — summer, fast of the 17th of Tammuz.
5. Av (אב) — Tishah BeAv, the saddest day.
6. Elul (אלול) — preparation for the High Holy Days.
7. Tishrei (תשרי) — Rosh Hashanah, Yom Kippur, Sukkot.
8. Cheshvan (חשוון) — autumn, no festivals (Mar Cheshvan, "bitter Cheshvan").
9. Kislev (כסלו) — Hanukkah.
10. Tevet (טבת) — fast of the 10th of Tevet.
11. Shevat (שבט) — Tu BiShevat, new year of the trees.
12. Adar (אדר) — Purim, joy.

In leap years, Adar II (אדר ב) is added, and Purim is celebrated in Adar II.

The Jewish Leap Year

To maintain alignment with the solar year and ensure festivals fall in their correct seasons (Passover in spring, Sukkot in autumn), the calendar adds an entire month seven times in a 19-year cycle (years 3, 6, 8, 11, 14, 17, and 19 of the Metonic cycle). The leap year has 13 months instead of 12.

Rosh Chodesh

The first day of each lunar month (Rosh Chodesh, ראש חודש) is a minor festival. It is announced in the synagogue on the preceding Shabbat. Traditionally, women rest from certain work on Rosh Chodesh, and in recent decades it has become a day of celebrating Jewish women's spirituality.

Shmitah (Sabbatical Year)

Every seventh year (shmitah, שמיטה), the Torah commands that the land of Israel rest: no planting or harvesting. Debts are forgiven. Today, the shmitah year is partially observed in Israel through legal mechanisms (heter mechirah) and in Orthodox communities through strict rules on produce importation.

Dating

The Hebrew year counts from the Creation of the world according to biblical chronology. The year 2026 of the Gregorian calendar corresponds approximately to Hebrew years 5786-5787. The Jewish New Year (Rosh Hashanah) falls in Tishrei.

Recommended reading: The Hebrew Calendar: A Scientific and Historical Study (Nathan Bushwick); The Jewish Calendar: Its Structure (E. J. Wiesenberg). The laws of Kiddush HaChodesh in the Mishnah (Rosh Hashanah) and Rambam (Hilchot Kiddush HaChodesh).