In the Gregorian calendar, Rosh Hashanah usually falls in which two-month span?

In the Gregorian calendar, Rosh Hashanah usually falls in September or October. The holiday begins on 1 Tishrei, the first day of the Hebrew calendar’s civil year. Because the Hebrew calendar is lunisolar rather than purely solar, that date moves against the Gregorian calendar from year to year, but it remains in the Northern Hemisphere’s early autumn.

Tishrei is the seventh month when the Hebrew months are counted from Nisan, the month associated with Passover, but it is the first month of the civil year. Rosh Hashanah therefore marks a new year for several religious and legal purposes, including calendar-year and sabbatical-year reckoning.

The exact Gregorian range is slightly broader in technical discussions: Rosh Hashanah has occurred as early as September 5 and as late as October 5. That is why “September or October” is the standard quiz answer, while “autumn” is a useful broader description.

A common mix-up is confusing Rosh Hashanah with Yom Kippur. Rosh Hashanah starts the High Holy Days and the Ten Days of Repentance; Yom Kippur follows ten days later, on 10 Tishrei.