Rosh Hashanah - Duration and Timing

Duration and Timing

Rosh Hashanah occurs 163 days after the first day of Passover (Pesach). In terms of the Gregorian calendar, the earliest date on which Rosh Hashanah can fall is September 5, as happened in 1899 and will happen again in 2013. The latest date that Rosh Hashanah can occur relative to the Gregorian dates is October 5, as happened in 1967 and will happen again in 2043. After 2089, the differences between the Hebrew calendar and the Gregorian calendar will result in Rosh Hashanah falling no earlier than September 6.

Although the Jewish calendar is based on the lunar cycle, so that the first day of each month originally began with the first sighting of a new moon, since the fourth century it has been arranged so that Rosh Hashanah never falls on a Wednesday, Friday, or Sunday.

The Torah defines Rosh Hashanah as a one-day celebration, and since days in the Hebrew calendar begin at sundown, the beginning of Rosh Hashanah is at sundown at the end of 29 Elul. The rules of the Hebrew calendar are designed such that the first day of Rosh Hashanah will never occur on the first, fourth, or sixth day of the Jewish week (i.e., Sunday, Wednesday, or Friday). Since the time of the destruction of the Second Temple of Jerusalem in 70 CE and the time of Rabban Yohanan ben Zakkai, normative Jewish law appears to be that Rosh Hashanah is to be celebrated for two days, due to the difficulty of determining the date of the new moon. Nonetheless, there is some evidence that Rosh Hashanah was celebrated on a single day in Israel as late as the thirteenth century CE. Orthodox and Conservative Judaism now generally observe Rosh Hashanah for the first two days of Tishrei, even in Israel where all other Jewish holidays dated from the new moon last only one day. The two days of Rosh Hashanah are said to constitute "Yoma Arichtah" (Aramaic: "one long day"). In Reform Judaism, some communities observe only the first day of Rosh Hashanah, while others observe two days. Karaite Jews, who do not recognize Rabbinic Jewish oral law and rely on their own understanding of the Torah, observe only one day on the first of Tishrei, since the second day is not mentioned in the Written Torah.