Why leap years create two Adars
Seven times every nineteen years, the Hebrew calendar adds Adar II to keep Pesach in spring. Ordinary years have one Adar. Leap years have Adar I and Adar II. If death occurred in Adar of a non-leap year, the next leap year forces a decision: observe in Adar I or Adar II?
Common rabbinic guidance (ask yours)
Widely taught Ashkenazi practice: in a leap year, observe the yahrzeit in Adar II when the original death was in regular Adar. Some cases differ if death was already in Adar I of a leap year. Because nuance matters, calculators encode standard rules but your rabbi should decide unusual cases.
Document the rabbi's answer in your reminder notes so siblings stay aligned.
What good yahrzeit software should do
A reliable yahrzeit calculator detects leap years and maps Adar correctly without manual edits. When comparing dates on paper, people often miss leap year logic and observe a week early or late.
Yahrzeit Alerts applies established Hebrew calendar rules, including Adar handling, so you are not re-learning leap year math every nineteen years.
Worked examples families ask about
If a parent passed on 10 Adar in a regular year, most calculators move the yahrzeit to 10 Adar II in the next leap year. The civil date might land near Purim, which is why siblings should confirm the date together in February rather than arguing in shul on the day itself.
If death occurred in Adar I during a leap year, the rule set differs. Do not assume the Adar II shortcut applies. Write down what your rabbi said the first time the question came up; leap years repeat on a nineteen-year cycle and the same confusion returns.
Non-Adar months still shift on the Gregorian calendar during leap years because the whole Hebrew year is longer. Only Adar creates the which-Adar question, but everyone feels the longer year's drift on plane tickets and hotel bookings.
Purim proximity and family gatherings
Adar yahrzeits often fall near Purim, when communities are busy with megillah and mishloach manot. Plan synagogue coordination early and consider a separate family meal if Purim joy collides with your private mourning customs.
Key takeaways
Leap-year Adar is the most common source of yahrzeit confusion after sunset questions.
Write your rabbi's ruling in your reminder app notes so every sibling sees the same Adar choice.
When Purim week is busy, confirm your synagogue schedule in advance so Kaddish and memorial candles align with the date you observe.
- Regular Adar deaths usually observe in Adar II during leap years
- Death in Adar I of a leap year follows different rules; ask your rabbi
- Trust calculators that encode standard Adar mapping
- Plan Purim-season logistics early when crowds are high