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How to make changes to a Yahrzeit + Anniversary calendar

This article describes how to make changes to a Yahrzeit + Anniversary calendar that you downloaded, exported or subscribed to in a calendar app like Outlook, Google Calendar / Android, or Apple (iOS, iPhone, iPad or Mac).

If you used Hebcal to create your personal calendar after August 2020 and you subscribed using the recommended feed option, you can click on the hebcal.com URL at the bottom of a calendar event. That link will take you back to the Yahrzeit and Anniversary calendar where you can make edits to each person’s name or dates.

If you subscribed to annual email reminders and did not synchronize your Apple/Google/Outlook calendar, you will find an “Edit Yahrzeit” link at the bottom of the reminder email message.

example email message including edit link

If you subscribed before August 2020, you will need to delete or unsubscribe the calendar containing your yahrzeit and anniversary reminders. Hebcal personal event calendars created before this date do not support editing event dates or names. Directions for how to delete/remove a subscribed calendar vary by calendar application. 

You may have downloaded yahrzeit/anniversary events and merged them into your regular personal calendar (often called “Home” or “Calendar”). To remove those events, search for the event(s) in your regular calendar and remove/delete them one at a time. These events will always have one of the following titles: “Yahrzeit”, “Hebrew Birthday” or “Hebrew Anniversary”.

Once you have removed the yahrzeit/anniversary calendar events, return to Hebcal.com and re-enter in all of the event details, then download again.

Yahrzeit + Anniversary API

We are pleased to offer experimental support for a yahrzeit API.

Clients should POST x-www-form-urlencoded data to https://www.hebcal.com/yahrzeit

The following parameters must be specified

  • cfg=json
  • v=yahrzeit

The following parameters may be specified once

  • years=3 – default 20. Use years=1 for only a single Hebrew year
  • hebdate=on – append Hebrew date to the event titles (default off)
  • yizkor=on – Include Yizkor dates (Pesach 8th day, Shavuot 2nd day, Yom Kippur and Shmini Atzeret — default off)
  • start=5749 – beginning Hebrew year to calculate anniversary dates (defaults the current Hebrew year)
  • end=5761 – ending Hebrew year (inclusive) to calculate anniversary dates (defaults to start year + years years)

Then, specify at least one input date based on the Gregorian date of death (or birth). The following parameters are required, substituting the X with increasing integers beginning with 1.

  • yX=1983 – Gregorian year, 4-digit date
  • mX=4 – Gregorian month, 1 or 2 digits (1=January, 12=December)
  • dX=15 – Gregorian day of month (1-31)
  • sX=on – Event occurred on Gregorian date after sunset (default off implies that event occurred before sunset)
  • tX=Yahrzeit – type (either Yahrzeit, Birthday or Anniversary)
  • nX=Plonit%20ben%20Ploni – name (optional)

Here is an example of two events, a Hebrew Birthday for Example1 and a Yahrzeit for Example2:

curl \
  --compressed \
  -H 'content-type: application/x-www-form-urlencoded' \
  --data-raw \
'cfg=json&v=yahrzeit&n1=Example1&t1=Birthday&d1=15&m1=4&y1=1983&s1=on&n2=Example2&t2=Yahrzeit&d2=13&m2=11&y2=2008&s2=off&hebdate=on&years=3' \
  'https://www.hebcal.com/yahrzeit'

The response will be text/json that looks like this:

{
   "title": "Hebrew Anniversaries: Example1, Example2",
   "date": "2021-05-12T17:52:44.991Z",
   "items": [
     {
       "title": "Example2's 12th Yahrzeit (15th of Cheshvan)",
       "date": "2020-11-02",
       "memo": "Hebcal joins you in remembering Example2, whose 12th Yahrzeit occurs on Monday, November 2, corresponding to the 15th of Cheshvan, 5781.\n\nExample2's Yahrzeit begins at sundown on Sunday, November 1 and continues until sundown on the day of observance. It is customary to light a memorial candle at sundown as the Yahrzeit begins.\n\nMay your loved one's soul be bound up in the bond of eternal life and may their memory serve as a continued source of inspiration and comfort to you."
     },
     {
       "title": "Example1's 38th Hebrew Birthday (3rd of Iyyar)",
       "date": "2021-04-15",
       "memo": "Hebcal joins you in honoring Example1, whose 38th Hebrew Birthday occurs on Thursday, April 15, corresponding to the 3rd of Iyyar, 5781.\n\nExample1's Hebrew Birthday begins at sundown on Wednesday, April 14 and continues until sundown on the day of observance."
     },
     {
       "title": "Example2's 13th Yahrzeit (15th of Cheshvan)",
       "date": "2021-10-21",
       "memo": "Hebcal joins you in remembering Example2, whose 13th Yahrzeit occurs on Thursday, October 21, corresponding to the 15th of Cheshvan, 5782.\n\nExample2's Yahrzeit begins at sundown on Wednesday, October 20 and continues until sundown on the day of observance. It is customary to light a memorial candle at sundown as the Yahrzeit begins.\n\nMay your loved one's soul be bound up in the bond of eternal life and may their memory serve as a continued source of inspiration and comfort to you."
     },
     {
       "title": "Example1's 39th Hebrew Birthday (3rd of Iyyar)",
       "date": "2022-05-04",
       "memo": "Hebcal joins you in honoring Example1, whose 39th Hebrew Birthday occurs on Wednesday, May 4, corresponding to the 3rd of Iyyar, 5782.\n\nExample1's Hebrew Birthday begins at sundown on Tuesday, May 3 and continues until sundown on the day of observance."
     },
     {
       "title": "Example2's 14th Yahrzeit (15th of Cheshvan)",
       "date": "2022-11-09",
       "memo": "Hebcal joins you in remembering Example2, whose 14th Yahrzeit occurs on Wednesday, November 9, corresponding to the 15th of Cheshvan, 5783.\n\nExample2's Yahrzeit begins at sundown on Tuesday, November 8 and continues until sundown on the day of observance. It is customary to light a memorial candle at sundown as the Yahrzeit begins.\n\nMay your loved one's soul be bound up in the bond of eternal life and may their memory serve as a continued source of inspiration and comfort to you."
     },
     {
       "title": "Example1's 40th Hebrew Birthday (3rd of Iyyar)",
       "date": "2023-04-24",
       "memo": "Hebcal joins you in honoring Example1, whose 40th Hebrew Birthday occurs on Monday, April 24, corresponding to the 3rd of Iyyar, 5783.\n\nExample1's Hebrew Birthday begins at sundown on Sunday, April 23 and continues until sundown on the day of observance."
     }
   ]
 } 

How does Hebcal determine anniversaries in Adar, Cheshvan, or Kislev?

Calendrical Calculations Hebcal uses the algorithm defined in Calendrical Calculations by Edward M. Reingold and Nachum Dershowitz.

Birthday

Reingold and Dershowitz write:

The birthday of someone born in Adar of an ordinary year or Adar II of a leap year is also always in the last month of the year, be that Adar or Adar II. The birthday in an ordinary year of someone born during the first 29 days of Adar I in a leap year is on the corresponding day of Adar; in a leap year, the birthday occurs in Adar I, as expected. Someone born on the thirtieth day of Marcheshvan, Kislev, or Adar I has his birthday postponed until the first of the following month in years where that day does not occur. [Calendrical Calculations p. 111]

Yahrzeit

The rule for a Yahrzeit is a little different:

The customary anniversary date of a death is more complicated and depends also on the character of the year in which the first anniversary occurs. There are several cases:

  • If the date of death is Marcheshvan 30, the anniversary in general depends on the first anniversary; if that first anniversary was not Marcheshvan 30, use the day before Kislev 1.
  • If the date of death is Kislev 30, the anniversary in general again depends on the first anniversary — if that was not Kislev 30, use the day before Tevet 1.
  • If the date of death is Adar II, the anniversary is the same day in the last month of the Hebrew year (Adar or Adar II).
  • If the date of death is Adar I 30, the anniversary in a Hebrew year that is not a leap year (in which Adar only has 29 days) is the last day in Shevat.
  • In all other cases, use the normal (that is, same month number) anniversary of the date of death.

[Calendrical Calculations p. 113]

Yahrzeit Example

For example, suppose Ploni ben Ploni passed away on 14 March 2001. That date corresponds to the 19th of Adar, 5761. Since 5761 was not a leap year, there was only one Adar that year (i.e. the date of death occurred in 12th month of the Hebrew year).

Suppose one wishes to observe the yahrzeit in Hebrew year 5765. Since 5765 is a leap year and none of the other rules applies, we use the same month number as the date of death. In a leap year the 12th month is Adar I, so the yahrzeit is observed on 19th of Adar I, 5765 (28 February 2005).

Variations

On page 114, Reingold and Dershowitz write:

There are minor variations in custom regarding the anniversary date in some of these cases. For example, Spanish and Portuguese Jews never observe the anniversary of a common-year date in Adar I.

There are undoubtedly many differing opinions regarding when to observe an Adar yahrzeit.

Here are two articles which offer differing opinions from our implementation:

For all matters of halacha, consult your local rabbi.

9 Feb 2005: added errata at Nachum Dershowitz’s request.
9 Mar 2005: Added Ploni ben Ploni example.
9 Mar 2014: Added links to opinions by Rabbis Golinkin and Schachter
28 Dec 2016: Corrected misspellings

Yahrzeit/Birthdays observed in Adar II

Last week I fixed a bug in yahrzeit calculations in the hebcal website.
Calendrical Calculations

According to Calendrical Calculations by Edward M. Reingold and Nachum Dershowitz, the yarhzeit of someone who passed away in Adar of an ordinary year or Adar II of a leap year is also always in the last month of the year, be that Adar or Adar II.

The hebcal.com website previously displayed those anniversaries as occurring in Adar I. Hebcal for Unix 3.3beta10 also contains this fix.