Jewish High Holidays 2024. The jewish calendar is a sophisticated, accurate system that has been in use for millennia. Rosh hashanah is the birthday of the universe, the day g‑d created adam and eve, and it’s celebrated as the jewish new year.it begins at sundown on the eve of tishrei 1 (oct.

11 and ends at sundown on saturday, oct. Shabbos nachamu and tu b’av: