The Hebrew calendar explained
The Hebrew (Jewish) calendar is lunisolar: its months follow the cycles of the moon, while the year is kept aligned with the solar seasons by periodically adding a leap month. That's why Jewish holidays fall on the same Hebrew date every year but shift around on the secular calendar — and why Passover always lands in spring and Sukkot in autumn. Understanding it makes the whole rhythm of the Jewish year click into place.
How does the lunisolar calendar work?
- Months follow the moon — each begins around the new moon (Rosh Chodesh) and runs 29 or 30 days, so a lunar year is about 11 days shorter than a solar year.
- Leap years add a month — to stop the holidays from drifting through the seasons, a 13th month (Adar II) is added in 7 of every 19 years.
- The result: holidays stay in their proper seasons while moving on the secular calendar.
What are the Hebrew months?
The twelve months are Nisan, Iyar, Sivan, Tammuz, Av, Elul, Tishrei, Cheshvan, Kislev, Tevet, Shvat, and Adar (with Adar I and II in a leap year). Each carries its own holidays and character — Tishrei holds the High Holy Days, Kislev brings Chanukah, Nisan brings Passover.
Why do Jewish holidays "move" each year?
They don't move on the Hebrew calendar — they're fixed there. They only appear to shift because the secular (solar) calendar and the Hebrew (lunisolar) calendar count time differently. The leap-month system keeps the two roughly in sync over the 19-year cycle.
In short: the Hebrew calendar is lunisolar — moon-based months, kept in season by leap months — which is why holidays hold their Hebrew date but shift on the secular calendar.
Learn the year with Derekh Learning
Derekh Learning's daily learning follows the Jewish calendar — holidays, parsha, and cycles — in a voice that fits you. Start learning or read what Rosh Chodesh is.
