Etching entitled: September (Settembre), Grape Harvest by Antonio Tempesta from his series: The Twelve Months (plate 9), 1599. September is the ninth month of the year in the Julian and Gregorian Calendars and one of four months with a length of 30 days. September (from Latin septem, meaning seven) retained its name after January and February were inserted into the calendar that had originally been created by the Romans.