Dear Rabbi,

My mother’s yahrtzeit, anniversary of passing, is on the 30th day of the Jewish month of Cheshvan. I was flipping through my Jewish calendar but couldn’t find the date!

Is it possible that it’s not there? What should I do?

Answer:

In the Jewish calendar all months have either 291 or 302 days. There are two months on the calendar, Cheshvan and Kislev, that some years have 29 days and other years have 30 days.

In a situation like this, when there are only 29 days in the month, the question becomes, ‘Do I observe the yahrtzeit a day earlier, Cheshvan 29, or a day later, Kislev 1?’

Because there are reasons to go either way,3 most opine4:

If the first year after the passing there was no 30th of Cheshvan, the yahrtzeit is observed on the 29th, and in all subsequent years that there is no Cheshvan 30 it should be observed on the 29th.

But, if in the first year after the passing Cheshvan did have a 30th day, then all subsequent years that do not have Cheshvan 30th, the yahrtzeit is observed on Kislev 1.

This same rule would apply for the 30th day of the month of Kislev.

While most do it this way, there are some who observe the yahrtzeit customs on both days.5

See our Yahrtzeit Calculator and Yahrzeit: Memorial Anniversary from our Jewish Death and Mourning minisite.