Can someone explain to me in simple language why my Jewish and English birthday are not on the same day this year. I will be 76 (4 time 19 ). My English is on Tuesday (today) and my Jewish one on Thursday. I was born at night before midnight. https://outorah.org/p/5696/

  • 6
    Mazal tov to you !
    – mbloch
    Feb 25 '20 at 8:53
  • 1
    Hi interested. I don't know how to answer your question because I don't know why you think your birthdays should be on the same day to explain to you why they aren't. Please edit to help clarify what you don't understand.
    – Double AA
    Feb 25 '20 at 13:31
  • @DonielF "" However, the test fails for Hebrew leap years. In any year except for a leap year, the above statement is accurate""" This year is not a leap year.
    – interested
    Feb 25 '20 at 14:07
  • In fact, possible times for your birthdays to coincide are after x*19, x*19+8 or x*19+11 years. In your case, the last time was in 2009, when you were 65, or 3*19+8.
    – Meir
    Feb 25 '20 at 15:48
  • @Meir I think you mean after x*8+y*11 years. It can happen on your 8th or 11th birthday too, before you ever turn 19. 19 is just the case where x=y=1.
    – Double AA
    Feb 25 '20 at 16:29

Mazal tov, Happy Birthday and ad 120! According to the interesting article you brought, the 19 year cycle of mirroring the two calendars is a misconception. What really happens in a 19 year cycle of the Jewish calendar is that there are a couple of rules that need to be kept constantly in order to properly maintain the solar & lunar calendar we use:

  1. Rosh Hashanah can't come out on Sunday, Wednesday or Friday (and subsequently, Pesach can't come out on Monday, Wednesday or Friday). To ensure this, changes are made to the months of Marcheshvan and/or Kislev of the previous year, depending on the circumstances.

  2. Leap years (Shanah Me'uberet) are made every 3rd, 6th, 8th, 11th, 14th, 17th and 19th year during the cycle. This is based on the old rule of adding a month so that Nissan and Pesach come out in the spring.

The kicker that ruins the mirroring of the calendars is therefore caused by the differences of Marcheshvan and Kislev every year and every cycle.

So in other words, the Jewish 19 year cycle is a concept used just to determine some of the rules of the calendar but isn't actually cyclical in practice (in terms of what Hebrew date comes out on what secular date).

  • @interested but Hebrew years aren't the same every 19 years. Now is 5780. Both Marcheshvan and Kislev had 29 days. In 5799 (provided that we won't have a Sanhedrin by then), Marcheshvan will be 29 days but Kislev will be 30 days.
    – Harel13
    Feb 25 '20 at 10:59
  • I am aware of all these things and it seem in 19 years the English years nearly always have the same total amount of days. Which is 19 times 365 plus 4 or 5 additional days for leap years equals 6939 or 6940. So one has to know all the possible amount of days possible for 19 years in the Jewish calender 6939-42 and how many was it in the last 19 years.
    – interested
    Feb 25 '20 at 11:06
  • So that means before 28 Feb, it has been 6939 English days (lowest) and 6940 Jewish days within the last 19 years. If I was born after midnight I would have been born on 26 Feb which is WED and my Jewish birthday on THU. I think that is right. That is if 19 years ago they were the same day. I cant say I remember.
    – interested
    Feb 25 '20 at 12:07
  • @interested 19 years ago, your English birthday fell out on 3 Adar (whereas, in 1944, it was on 2 Adar): hebcal.com/converter/?gd=26&gm=2&gy=2001&g2h=1
    – Loewian
    Feb 25 '20 at 15:05
  • @Loewian Thanks for link.Using 26 FEB 44, 63 =2 Adar. 82, 01 = 3 Adar 2020 = 1 Adar. 2039=2 Adar. I dont understand how it jumped back this year 2 days. Unless my figures for possible amount above are incorrect.
    – interested
    Feb 25 '20 at 16:37

Not the answer you're looking for? Browse other questions tagged .