Tishrei

Tishrei is the seventh month of the Hebrew year in the festival reckoning, but it opens the civil year and holds more festivals than any other month. Falling in early autumn, roughly September to October, it is aligned in tradition with the sign of Libra and counts thirty days. It begins with Rosh Hashanah, the new year, on the first and second; the ten days of repentance culminate in Yom Kippur, the Day of Atonement, on the tenth, the most solemn fast of the year; and the joyous festival of Sukkot follows from the fifteenth, closing with Shemini Atzeret and Simchat Torah. Its name is glossed with the sense of beginning. The Hebrew calendar is lunisolar, kept in step with the solar year by a leap month. These are the observances of the Jewish calendar tradition.

Tishrei opens the civil new year, Rosh Hashanah, on the first, and carries within its first ten days the Aseret Yemei Teshuvah, the Ten Days of Repentance, culminating in Yom Kippur on the tenth, the most solemn fast of the Hebrew calendar. Five days later the harvest festival of Sukkot begins, running seven days and followed immediately by Shemini Atzeret and, outside Israel, Simchat Torah on a further added day, so that Tishrei carries a denser concentration of major festivals than any other month in the calendar. Because Rosh Hashanah's date depends on the molad, the calculated mean lunar conjunction, and on the dechiyot, the postponement rules, it can fall on any of four different weekdays but never on a Sunday, Wednesday or Friday, a restriction built into the fixed calendar's own arithmetic.

The name comes from the Akkadian Tashritu, one of the Babylonian month names adopted wholesale into Hebrew usage. The month runs a fixed 30 days in every year.

The month names are Babylonian. Twelve of them are the Akkadian month names taken into Hebrew during and after the exile, and the biblical books of the return use them freely while the earlier books generally number the months or use a small set of older Canaanite names. The atlas records the borrowing rather than presenting the names as native, because it is one of the clearest visible marks the exile left on Jewish practice.

The Jewish calendar as now kept is calculated rather than observed. Month lengths are fixed by rule except for Cheshvan and Kislev, which absorb the adjustment and may run 29 or 30 days, and a thirteenth month is added in seven years out of nineteen on a fixed cycle so that Passover stays in the spring. A further set of rules, the postponements, shifts Rosh Hashanah off certain weekdays, which is why the year has six possible lengths rather than two.

Tishrei is the seventh month by the biblical count and the first by the reckoning in which the year number advances, and it is the densest month of the calendar: Rosh Hashanah, Yom Kippur and Sukkot all fall within it. The postponement rules exist principally to control where in the week its festivals land.