Jewish holidays

Description

Most Jewish festivals, holidays and feasts are celebrated on fixed days in the Hebrew calendar, but some events are celebrated earlier of later under some circumstances.

Determining the date of an Jewish observance, festival, holiday or feast can be done by using the HebrewDateInOrAfterCivilYear and HebrewDateInOrBeforeCivilYear routines.

Since the Jewish year can be both sorter and longer than the Civil (Gregorian) or Julian year, it is possible that the specified Jewish observance, festival, holiday or feast occurs twice in the given Civil (Gregorian) or Julian year or does not occur in the specified Civil (Gregorian) or Julian year at all.

HebrewDateInOrAfterCivilYear can be used to determine the first occurence of a Jewish festival, holiday or feast in a given Civil (Gregorian) or Julian year. If the specified Jewish festival, holiday or feast does not occur in the given Civil (Gregorian) or Julian year, then the routine detemines the date of the first occurence of a Jewish festival, holiday or feast in the next Civil (Gregorian) or Julian year.

HebrewDateInOrBeforeCivilYear can be used to determine the last occurence of a Jewish festival, holiday or feast in a given Civil (Gregorian) or Julian year. If the specified Jewish festival, holiday or feast does not occur in the given Civil (Gregorian) or Julian year, then the routine detemines the date of the last occurence of a Jewish festival, holiday or feast in the previous Civil (Gregorian) or Julian year.

There are some complications in the Hebrew Calendar. First of all there's the question when the new year starts. The New Year can be said to begin on the 1st of Nisan (Leviticus 23:5) or on Rosh Hashanah, the 1st of Tishri (Leviticus 23:24). We will assume that Rosh Hashanah is the first day of the year.

Another complication in the Hebrew calendar is that leap years have an extra month inserted between the fifth month (called Shevat) and sixth month (called Adar). The extra month is called Adar I and the "normal" month Adar is named Adar II. So retreiving the Gregorian if Julian date of the first of Nisan (the month after Adar or Adar II) might be cumbersome if you don not know whether de Hebrew year is a leap year or not. To make things easier, the routines HebrewDateInOrAfterCivilYear and HebrewDateInOrBeforeCivilYear accept a negative number for the month. -1 means the last month of the year (Elul), -1 the last but one month (Av), etcetera.

Note that you must take care of any postponement or advancement rules yourself. See the notes in "Gory details" and the example of Yom Tammuz.

Gory details

Here's an overview of the major observances, festivals, holidays and feasts.The numbers between brackets in the second column represent the month and day that you should pass to HebrewDateInOrAfterCivilYear or HebrewDateInOrBeforeCivilYear

¹ Postponed one day if it would fall on the Sabbath.
² Occurs two days earlier if it would fall on the Sabbath.
³ Occurs on the Thursday preceding if it would fall on the Friday or the Sabbath.
⁴ Occurs one day later if it would fall on a Sunday (since May 1997)
⁵ Occurs on the Wednesday following if it would fall on a Thursday or Friday.
⁶ The Omer (heave offering) is the period of 49 days following the first day of Passover.

Examples

In the first example both HebrewDateInOrAfterCivilYear and HebrewDateInOrBeforeCivilYear return the Juliand Day Number 2452254, which corresponds to December 10, 2001

Const Gregorian = 1

hannukah = HebrewDateInOrBeforeCivilYear(2001, 3, 25, Gregorian)
hannukah = HebrewDateInOrAfterCivilYear(2001, 3, 25, Gregorian)

In the next example HebrewDateInOrAfterCivilYear returns 2828091 and HebrewDateInOrBeforeCivilYear return 2828475, which correspond to December 13, 3030 and January 1, 3032 respectively. This means that there is no (first day of) Hannukah in the Civil (Gregorian) year 3031!)

Const Gregorian = 1

hannukah = HebrewDateInOrBeforeCivilYear(3031, 3, 25, Gregorian)
hannukah = HebrewDateInOrAfterCivilYear(3031, 3, 25, Gregorian)

In the next example HebrewDateInOrAfterCivilYear returns 2828828 and HebrewDateInOrBeforeCivilYear return 2828476, which correspond to December 19, 3032 and January 1, 3032 respectively. This means that Hannukah starts in the Civil (Gregorian) year 3032 twice!

Const Gregorian = 1

hannukah = HebrewDateInOrBeforeCivilYear(3032, 3, 25, Gregorian)
hannukah = HebrewDateInOrAfterCivilYear(3032, 3, 25, Gregorian)

In the next example HebrewDateInOrBeforeCivilYear returns 2451978, which correspond to March 9, 2001.

Const Gregorian = 1

purim = HebrewDateInOrBeforeCivilYear(2001, -7, 14, Gregorian)

In the next example HebrewDateInOrBeforeCivilYear returns 2451978, which correspond to March 9, 2001.

Const Gregorian = 1

purim = HebrewDateInOrBeforeCivilYear(2001, -7, 14, Gregorian)

In the next example HebrewDateInOrBeforeCivilYear returns 2456116, which correspond to July 7, 2012. But because this day is Sabbath (Saturday, dayofweek returns 6)), Yom Tammuz is postponed one day.

Const Gregorian = 1

yomtammuz = HebrewDateInOrBeforeCivilYear(2012, -3, 17, Gregorian)
If (dayofweek(yomtammuz,1) = 6) Then
    yomtammuz = yomtammuz + 1
End If

See also

HebrewDateInOrBeforeCivilYear, HebrewDateInOrAfterCivilYear, dayofweek, The Worldwide Holiday and Festival Site

Related links

Send an e-mail card for Hannukah or other Jewish events.

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