Dating of jewish calendar
The Jewish calendar remained unchanged during the period between the Old Testament and New Testaments (approximately 400 years), despite an attempt by Hellenistic rulers to introduce a modified lunar-month system, presumably of Macedonian origin.
According to that calendar, five days were added to the final month of the year, with each of the 12 months containing 30 days. Usually, the ancient Hebrews did not record dates by citing the month and day of an event.
Before the Babylonian exile, at least four months had other names: Abib (Exodus 13:4), Ziv (1 Kings 6:1, 37), Ethanim ( 1 Kings 8:2), and Bul (1 Kings ).
All Jewish holidays begin in the evening after the sunset.