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/
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:
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.
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).