What are the Jewish holidays? They are listed at the end of this page in calendar order. However, they aren't on the same day every year. Why? It all has to do with calendars and history.
The Jewish calendar vs. the Gregorian calendar
The Gregorian calendar is the most familiar calendar to much of the world. A Gregorian calendar year contains 365 days, begins in January, and runs through December. The day begins and ends at midnight.
The Jewish calendar is based on the lunar cycle that was set forth by God in the Hebrew Scriptures (Old Covenant). The Jewish calendar year contains 360 days running from the months of Tishri through Elul. On the Gregorian calendar, Tishri falls in either September or October and Elul in August or September. Also, in the Jewish calendar system, a day begins and ends at sunset.