Tishrei is the Hebrew calendar month in which Rosh Hashanah, the Jewish new year, begins.
Rosh Hashanah begins on the first day of Tishrei. The month also contains Yom Kippur, Sukkot, Shemini Atzeret, and Simchat Torah, making it one of the most eventful periods in the Jewish calendar. These dates are relevant to bar and bat mitzvah planning because ceremonies are scheduled by Hebrew date.
A child’s Hebrew birthday can fall on a different Gregorian date each year. Families therefore consult a Hebrew-calendar conversion and their synagogue’s calendar when arranging a ceremony. In leap years, the Hebrew calendar adds an extra month elsewhere in the year, but Tishrei remains the seventh month when counted from Nisan and the first month for the civil new year.
Tishrei should not be confused with Nisan, which begins the biblical festival cycle associated with Passover. The two months have different calendar roles and traditions.