Christians claim that Jesus was put to death on Passover eve Nisan 14 they make the date for easter based on the first full moon after the spring equinox(paschal full moon)

This year (2016) Passover is not until April 22 but that is not on paschal full moon. Spring equinox is March 20 and first full moon after is March 23.

Is it important that Passover be held on first full moon following the vernal equinox?

  • 2
    Note to VTCers: motivation by other religions does not mean comparative religion. The question is if, based on Jewish sources, it’s important for Pesach to be the full moon after the vernal equinox, regardless of the Christian prologue. Comparative religion requires knowledge of other religions, which is not the case here.
    – DonielF
    Commented Mar 25, 2018 at 1:24

3 Answers 3


Your question and DoubleAA's comment on my original answer have inspired me to do some research and learn some really fascinating information about the Hebrew calendar.

First, some background information:

Our current 19-year intercalary cycle was instituted by Hillel II in the fourth century CE. The calendar is a lunisolar calendar which typically has 12 months. A normal year is 354 days, which is approximately 11.25 days shorter than the solar calendar. To correct for this, the Hebrew calendar has a leap year every 2 or 3 years for a total of 7 times every 19 years. In those leap years, instead of a single day (which we add to our solar calendar), an entire month is added.

Now your question:

According to Wikipedia, at the time when the calendar started, the earliest Passover (corresponding to the 16th year of the 19-year cycle) fell on the vernal equinox and Passover always fell on the first full moon following the equinox.

Over the centuries, there has been a very slight seasonal drift in the calendar (the average year is just over 6.5 minutes longer than the Gregorian calendar). As a result, the calendar has shifted about 7 and a half days later relative to the equinox. But since the months themselves cannot be shifted by a full week (since the new month is tied to the new moon) the result is that in certain leap-years, the leap-month which is supposed to correct for the drift is inserted a year earlier than it should have been to actually match the equinox. This currently happens in the 8th, 11th, and 19th years of the 19-year cycle. Basically, in those years, there has been one more leap year than there actually "should have been" between the fourth century and today.

As you mentioned, this year Passover is not on the first full moon following the vernal equinox. That is because, this year is the 19th year of the current 19-year cycle, which is one of the years where the leap-month is added "prematurely". At this point, there is not much concern about Passover occasionally falling out on the second full moon after the equinox. There is no requirement in the Torah that it fall on the first full moon. There is, however, a requirement that Passover must fall in the Spring (it is called the Spring Festival). If the current calendar were to be followed indefinitely, Passover would eventually fall in the summer due to continued seasonal drift. This would be problematic, but it is not of immediate concern because it would take millenia for this to happen. The hope is that the messiah will come well before then and re-introduce the court-based institution of the months and leap years.

Some bonus information:

You may have noticed that I mentioned that our current calendar was instituted in the fourth century. Of course, the time period that Christians are interested in occurred before this time. Prior to the establishment of the fixed (calculated) calendar, the leap years were determined by the courts. The main factors that the courts took into account was the relationship between Passover and the equinox. They needed to make sure that Passover always fell after the vernal equinox. In addition, however, they could consider other factors that affected the ability of the people living throughout Israel to properly observe the Pesach festival. If the winter rains had destroyed the roads and bridges (which would prevent people from far away from making the festival pilgrimage) or they had destroyed the ovens for roasting the paschal sacrifice, the courts could institute a leap year in order to allow an extra month for the roads and ovens to be fixed before the festival (see Rambam - Mishneh Torah, Kiddush HaChodesh, Chapter 4, Halakha 5).

In a year which was declared a leap-year for one of those reasons, it is entirely likely that such an additional month would push Passover to the second full moon following the equinox. So even before the set calendar and seasonal drift, it was possible for Passover to fall out not on the first full moon. I am not aware of how often this happened (if it ever actually happened at all), but it is most likely (in my opinion) that Passover did occur in the first full moon following the equinox (as it does in most years now and probably in almost all years back then) in the year Christians believe Jesus was killed .

  • Daniel, your explanation, esp. near the end of the 2n d paragraph is concise and accurate. Kudos! I think that you and, perhaps, O.P. would be interested in at least 2 articles that discuss the seasonal shift. One of them is written by Remi Landau. I'll try to post them, here, tomorrow. Otherwise, please remind me. If OK with you, I prefer to edit this into your answer, once I find them.
    – DanF
    Commented Feb 29, 2016 at 2:33
  • I talk about what dates the calendar could have at What will happen to the calendar if the Sanhedrin is re-instituted Commented Feb 29, 2016 at 2:43
  • Very much appreciated Daniel I would love to get your answer posted over on CSE it explains why Passover is a month behind Easter this year
    – Kris
    Commented Feb 29, 2016 at 16:08
  • If you still check in here I have a further question.dies the month of Nisan have to start on a new Minnesota that follows the equinox?
    – Kris
    Commented Mar 7, 2018 at 1:45
  • @Kris No, the beginning of Nisan often falls before the equinox. Passover must always begin some time after the equinox, though not necessarily right away. It could be a month later (or some day in the very distant future it could be two months later). As I said in the answer, when the our fixed calendar was first established, Passover fell on the vernal equinox in the 16th year of the 19 year cycle so the month of Nisan would have started 15 days before the equinox in that year.
    – Daniel
    Commented Mar 8, 2018 at 2:36

The Spring Equinox this year is March 2o, 2018. The first new moon after that is April 15-16 (depending on witnesses observations). The first full moon would be 2 weeks later, April 29-30, marking the start of the actual Passover this year IF one follows Torah's instructions. There is already a Sanhedrin in Israel that correctly declared the full moon last year yet we apparently are ignoring their declarations and choosing instead to continue to follow Hillel's fixed (and thus convenient) calendar.

  • Using Chabad’s handy little Molad chart, one sees that this is indeed considered the new moon even according to the Jewish calendar, except that it’s that of Iyar. The problem is that this is the new moon of Iyar. If we use the new moon of Nissan as recorded there at March 17, the previous new moon, then Pesach falls out correctly. The reason for this discrepancy is that for all halachic intents and purposes we follow the Julian calendar’s assessment of the vernal equinox, which these days is March 7.
    – DonielF
    Commented Jan 28, 2018 at 18:58
  • TL;DR, then, is that this is technically correct until one considers how Halacha determines the vernal equinox.
    – DonielF
    Commented Jan 28, 2018 at 19:05
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    Why do you insert a required new moon between the equinox and the full moon? (Not that we count by equinoxes, but the christian claim asked about in the question doesn't involve new moons at all; in fact, they consider a full moon a few days after the equinox to be the date for Passover.) Commented Jan 28, 2018 at 20:24

Most likely it is not correct assumption, because one of the theories about Hebrew calendar states that 15th is always a Shabbat, which will put Passover roughly right after equinox. But I checked, and in such system Passover would not always be the first Shabbat right after equinox, but very close, most likely second. So if Christian messiah was operating on a Lunar Shabbat calendar, this may be correct way to determine the Passover. As far as I can tell, Holy Meetings such as Passover are not tied to the astronomic events such as equinox, but they do happen during equinox/solstice times. This is probably to avoid worshiping the sun. So, the answer to OP would be maybe but probably not.

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    "15th is always a Shabbat, which will put Passover roughly right after equinox" how does that follow?
    – Daniel
    Commented Feb 28, 2016 at 20:58
  • The 15th is only on a Shabbat if you’re a Saducee or Karaite or the like. See further here.
    – DonielF
    Commented Jan 28, 2018 at 19:04

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