Hebrew/Jewish calendar

The ancient Hebrew/Jewish calendar differed from our modern-day calendar system and thus dates/times in the Bible can be confusing if one does not understand how the ancient Hebrew calendar was used to record time.

The Hebrew calendar was a lunar calendar and thus, projected a shorter year than a solar calendar (about 11 days shorter). To compensate for the missing days, the Hebrew calendar added an additional month every two or three years (when to add the extra month was based on observation of agriculture-related events). The Hebrew calendar was gradually replaced by a modern-day mathematical calendar from 200 – 500 AD.

Days had no fixed length but rather ran from sunset to sunset. An hour was 1/24 of this period and thus, hours in winter were much shorter and much longer in summer.

Below are notable biblical calendar systems you will encounter in your bible studies.

Hebrew weekdays

  1. Sunday – Yom Rishon – “first day”
  2. Monday – Yom Sheni – “second day”
  3. Tuesday – Yom Shlishi – “third day”
  4. Wednesday – Yom Revi’I – “fourth day”
  5. Thursday – Yom Chamishi – “fifth day”
  6. Friday – Yom Shishi – “sixth day”
  7. Saturday – Yom Shabbat – “Sabbath rest day”

Hebrew months

  1. Nisan (30 days)
  2. Iyyar (29 days)
  3. Sivan (30 days)
  4. Tammuz (29 days)
  5. Av (30 days)
  6. Elul (29 days)
  7. Tishrei (30 days)
  8. Marcheshvan (aka Cheshvan) (29/30 days)
  9. Kislev (30/29 days)
  10. Tevet (29 days)
  11. Shevat (30 days)
  12. Adar (29 days)
  13. Adar 1 (30 days – leap month – occurs every 2-3 years)

Unknown calendar

The Bible mentions other months hinting at a calendar that pre-dated the Hebrew calendar. The months are suspected to be Canaanite names and include:


Aviv – first month – “spring”

Ziv – second month – “light”

Ethanim – seventh month – “strong”

Bul – eighth month

Babylonian calendar (Hebrew equivalent in parenthesis)

The Babylonian calendar differed slightly from the Hebrew calendar.

  1. Nisanu (Nisan)
  2. Ayaru (Iyyar)
  3. Simanu (Sivan)
  4. Dumuzu (Tammuz)
  5. Abu (Av)
  6. Ululu (Elul)
  7. Tashritu (Tishri)
  8. Arakhsamna (Marcheshvan)
  9. Kisiimu (Kislev)
  10. Tebetu (Tevet)
  11. Shabatu (Shvat)
  12. Adaru (Adar)
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