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September, from the Très Riches Heures du Duc de Berry
School starts in September in many countries, such as Belgium
WPA poster, 1940
Sapphire, September birthstone
Forget-me-not, September birth flower

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.

September in the Northern Hemisphere and March in the Southern Hemisphere are seasonally equivalent.

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. 

September marks the beginning of the ecclesiastical year in the Eastern Orthodox Church. It is the start of the academic year in many countries of the northern hemisphere, in which children go back to school after the summer break, sometimes on the first day of the month.

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. 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.


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.

In 1752, the British Empire adopted the Gregorian calendar. In the British Empire that year, September 2 was immediately followed by September 14.

On Usenet, it is said that September 1993 (Eternal September) never ended.

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).

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.


September's birthstone is the sapphire. The birth flowers are the forget-me-not, morning glory and aster. The zodiac signs are Virgo (until September 22) and Libra (September 23 onward).

Morning glories
Morning glories


This list does not necessarily imply either official status or general observance.



United States

Food months

Movable Gregorian

First Wednesday

First Thursday

First Friday

First Sunday

First Sunday after September 4

Week of the first Monday

Week of September 10

First Monday

Nearest weekday to September 12

Second Saturday

Saturday after first Monday

Second Sunday

First Sunday after first Monday

Week of September 17

Third Tuesday

September 17 but observed on previous Friday if it falls on a Saturday or following Monday if on a Sunday

Third Friday

Third Saturday

Weekend of the week of September 17

Third Sunday

Week of Sunday before September 23

Week of September 22

Last week

Last full week

Third Monday

Pertaining to the September Equinox

Fourth Friday

Last Friday

Last Saturday

Last Sunday

Fourth Monday

Last Wednesday

Last weekday

Fixed Gregorian

This page was last updated at 2024-04-07 09:19 UTC. Update now. View original page.

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