Learn the Hebrew Calendar
Names of weekdays
The Hebrew calendar follows a seven-day weekly cycle, which runs concurrently with but independently of the monthly and annual cycles. The names for the days of the week are simply the day number within the week. In Hebrew, these names may be abbreviated using the numerical value of the Hebrew letters, for example יום א׳ (Day 1, or Yom Rishon (יום ראשון)):
The Hebrew calendar follows a seven-day weekly cycle, which runs concurrently with but independently of the monthly and annual cycles. The names for the days of the week are simply the day number within the week. In Hebrew, these names may be abbreviated using the numerical value of the Hebrew letters, for example יום א׳ (Day 1, or Yom Rishon (יום ראשון)):
- Yom Rishon – יום ראשון (abbreviated יום א׳), meaning "first day" [corresponds to Sunday] (starting at preceding sunset of Saturday)
- Yom Sheni – יום שני (abbr. יום ב׳) meaning "second day" [corresponds to Monday]
- Yom Shlishi – יום שלישי (abbr. יום ג׳) meaning "third day" [corresponds to Tuesday]
- Yom Reviʻi – יום רביעי (abbr. יום ד׳) meaning "fourth day" [corresponds to Wednesday]
- Yom Chamishi – יום חמישי (abbr. יום ה׳) = "fifth day" [corresponds to Thursday]
- Yom Shishi – יום ששי (abbr. יום ו׳) meaning "sixth day" [corresponds to Friday]
- Yom Shabbat – יום שבת (abbr. יום ש׳), or more usually Shabbat – שבת
MonthsThe Hebrew calendar is a lunisolar calendar, meaning that months are based on lunar months, but years are based on solar years.[11] The calendar year features twelve lunar months of twenty-nine or thirty days, with an intercalary lunar month added periodically to synchronize the twelve lunar cycles with the longer solar year. (These extra months are added seven times every nineteen years. See Leap months, below.) The beginning of each Jewish lunar month is based on the appearance of the new moon.[12] Although originally the new lunar crescent had to be observed and certified by witnesses,[13] the moment of the true new moon is now approximated arithmetically as the molad, which is the mean new moon to a precision of one part.
The mean period of the lunar month (precisely, the synodic month) is very close to 29.5 days. Accordingly, the basic Hebrew calendar year is one of twelve lunar months alternating between 29 and 30 days:
No.Hebrew monthsLength
1 Nisan30
2 Iyar29
3 Sivan30
4 Tammuz29
5 Av30
6 Elul29
7 Tishrei30
8 Marcheshvan
(or Cheshvan)29/30
9 Kislev30/29
10 Tevet29
11 Shevat30
12 Adar29
Total353, 354 or 355In leap years (such as 5774) an additional month, Adar I (30 days) is added after Shevat, while the regular Adar is referred to as "Adar II."
The insertion of the leap month mentioned above is based on the requirement that Passover—the festival celebrating the Exodus from Egypt, which took place in the spring—always occurs in the [northern hemisphere's] spring season. Since the adoption of a fixed calendar, intercalations in the Hebrew calendar have been assigned to fixed points in a 19-year cycle. Prior to this, the intercalation was determined empirically:
The year may be intercalated on three grounds: 'aviv [i.e.the ripeness of barley], fruits of trees, and the equinox. On two of these grounds it should be intercalated, but not on one of them alone.[14]
The mean period of the lunar month (precisely, the synodic month) is very close to 29.5 days. Accordingly, the basic Hebrew calendar year is one of twelve lunar months alternating between 29 and 30 days:
No.Hebrew monthsLength
1 Nisan30
2 Iyar29
3 Sivan30
4 Tammuz29
5 Av30
6 Elul29
7 Tishrei30
8 Marcheshvan
(or Cheshvan)29/30
9 Kislev30/29
10 Tevet29
11 Shevat30
12 Adar29
Total353, 354 or 355In leap years (such as 5774) an additional month, Adar I (30 days) is added after Shevat, while the regular Adar is referred to as "Adar II."
The insertion of the leap month mentioned above is based on the requirement that Passover—the festival celebrating the Exodus from Egypt, which took place in the spring—always occurs in the [northern hemisphere's] spring season. Since the adoption of a fixed calendar, intercalations in the Hebrew calendar have been assigned to fixed points in a 19-year cycle. Prior to this, the intercalation was determined empirically:
The year may be intercalated on three grounds: 'aviv [i.e.the ripeness of barley], fruits of trees, and the equinox. On two of these grounds it should be intercalated, but not on one of them alone.[14]