November ( ) is the eleventh month of the year in the Julian and Gregorian Calendars and one of four months with the length of 30 days. November was the ninth month of the ancient Roman calendar. November retained its name (from the Latin novem meaning "nine") when January and February were added to the Roman calendar. November is a month of spring in the Southern Hemisphere and autumn in the Northern Hemisphere. Therefore, November in the Southern Hemisphere is the seasonal equivalent of May in the Northern Hemisphere and vice versa.