The Hebrew month of Tishrei falls during the months of September and October. Since the 12-month Jewish calendar follows the lunar year, its months are a few days shorter and thus its holidays vary year to year in the Gregorian calendar.
The month of Tishrei marks the very start of the Jewish year. Tishrei is a month of holidays. Four Jewish holidays are celebrated this month: Jewish New Year, Yom Kippur, Sukkot and Simhat Torah.