The answer
This is because the current Jewish calendar was not in effect at the time of the Crucifixion. The date of the Jewish Passover originally depended on the date of the spring harvest in Palestine. After the rebellion of Simon bar Kochba in AD 135, it became impossible to determine the date of Passover, because the Romans banned all Jews from Jerusalem. (The ban lasted for centuries.) So the rabbis reformed the Jewish calendar at least twice, the first time was about AD 200.Answered by His Eminence Metropolitan Youssef (opens in a new tab)