September is the ninth month of the year in both the
Gregorian calendar and the less commonly used
Julian calendar. In the modern Gregorian calendar, its length is 30 days.
In the Northern hemisphere, the beginning of the meteorological
autumn is on 1 September. In the Southern hemisphere, the beginning of the meteorological
spring is on 1 September.[1]
September (from Latin septem, "seven") was originally the seventh of ten months in the oldest known
Roman calendar, the
calendar of Romulus
c. 750 BC, with March (Latin Martius) the first month of the year until perhaps as late as 451 BC.[2] After the calendar reform that added
January and
February to the beginning of the year, September became the ninth month but retained its name. It had 29 days until the Julian reform, which added a day.
Events
Ancient Roman observances for September include
Ludi Romani, originally celebrated from September 12 to September 14, later extended to September 5 to September 19. In the 1st century BC, an extra day was added in honor of the deified Julius Caesar on 4 September.
Epulum Jovis was held on September 13.
Ludi Triumphales was held from September 18–22. The
Septimontium was celebrated in September, and on December 11 on later calendars. These dates do not correspond to the modern Gregorian calendar.
September was called "harvest month" in
Charlemagne's calendar. September corresponds partly to the
Fructidor and partly to the
Vendémiaire of the
first French republic. September is called Herbstmonat, harvest month, in Switzerland. The
Anglo-Saxons called the month Gerstmonath, barley month, that crop being then usually harvested.[3]
In the United States, September is one of the most common birth months (third most popular after August and July, which both have 31 days), as all but one Top 10 most common birthdays are in September, based on the
National Center for Health Statistics statistics on births between 1994 and 2014. The most common birthday is September 9 (#1), least common is September 1 (#250).[4][5][6]
Astronomy and astrology
The
September equinox takes place in this month, and certain observances are organized around it. It is the
Autumn equinox in the Northern Hemisphere, and the
Vernal equinox in the Southern Hemisphere. The dates can vary from 21 September to 24 September (in
UTC).
September is mostly in the sixth month of the astrological calendar (and the first part of the seventh), which begins at the end of March/Mars/Aries.
^H.H. Scullard, Festivals and Ceremonies of the Roman Republic (Cornell University Press, 1981), p. 84; Gary Forsythe, Time in Roman Religion: One Thousand Years of Religious History (Routledge, 2012), p. 14.