September is the ninth month of the year in both the Gregorian calendar and the less commonly used Julian calendar. In modern day, September has 30 days. September in the Northern Hemisphere and March in the Southern Hemisphere are seasonally equivalent.
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 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 edit
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.
This list does not necessarily imply either official status or general observance.
- List of observances set by the Bahá'í calendar
- List of observances set by the Chinese calendar
- List of observances set by the Hebrew calendar
- List of observances set by the Islamic calendar
- List of observances set by the Solar Hijri calendar
- Amerindian Heritage Month (Guyana)
- Childhood Cancer Awareness Month (United Kingdom)
- Gynecologic Cancer Awareness Month
- Leukemia and Lymphoma Awareness Month
- Ovarian Cancer Awareness Month
- Thyroid Cancer Awareness Month
- National Suicide Prevention Month
- Vegetable Month
United States edit
- Better Breakfast Month
- Food Safety Education Month
- National Childhood Obesity Awareness Month
- Hydrocephalus Awareness Month
- Pain Awareness Month
- National Preparedness Month
- National Prostate Health Month
- National Sickle Cell Awareness Month
- National Yoga Month
Food months edit
- National Bourbon Heritage Month
- California Wine Month
- National Chicken Month
- National Honey Month
- National Mushroom Month
- National Italian Cheese Month 
- National Papaya Month
- National Potato Month
- National Rice Month
- National Whole Grains Month
- National Wild Rice Month
Movable Gregorian edit
- Engineering Day (Egypt)
- White Balloon Day
- Day of the Programmer
- Te Wiki o te Reo Māori (Māori Language Week) (New Zealand)
- See also Movable Western Christian observances
- See also Movable Eastern Christian observances
First Wednesday edit
First Thursday edit
First Friday edit
First Sunday edit
- Brazilian Day (International observance)
- Father's Day (Australia, Fiji, New Zealand, Papua New Guinea)
- Memorial of the Holy Guardian Angels (Roman Catholic Church, October 2 in most locations, first Sunday in September by special dispensation)
First Sunday after September 4 edit
- Wakes Week (Parts of England and Scotland)
Week of the first Monday edit
Week of September 10 edit
First Monday edit
Nearest weekday to September 12 edit
Second Saturday edit
Saturday after first Monday edit
Second Sunday edit
- Auditor's Day (Church of Scientology)
- Father's Day (Latvia)
- National Grandparents' Day (Canada, Estonia)
- Tanker's Day (Russia)
- Turkmen Bakhshi Day (Turkmenistan)
First Sunday after first Monday edit
Week of September 17 edit
Third Tuesday edit
September 17 but observed on previous Friday if it falls on a Saturday or following Monday if on a Sunday edit
Third Friday edit
Third Saturday edit
- National Cleanup Day (United States)
- Oktoberfest celebrations begin (German diaspora, local dates may vary)
- Software Freedom Day (International observance)
Weekend of the week of September 17 edit
Third Sunday edit
- Day of the Walloon Region (Wallonia, Belgium)
- Father's Day (Ukraine)
- Federal Day of Thanksgiving, Repentance and Prayer (Switzerland)
- Warachikuy (Cusco, Peru)
Week of Sunday before September 23 edit
Week of September 22 edit
Last week edit
Last full week edit
- National Forest Week (Canada)
- National Tree Day (Wednesday of last full week):
- Celebrate Freedom Week (Arkansas and Florida, United States)
Third Monday edit
Pertaining to the September Equinox edit
- Autumnal Equinox Day (Japan)
- French Republican New Year. (defunct)
- Guldize (Cornish people)
- Higan (Japan)
- Mabon (Neopaganism, Northern Hemisphere)
- Miķeļi (Latvia)
- Ostara (Neopaganism, Southern Hemisphere)
Fourth Friday edit
Last Friday edit
Last Saturday edit
Last Sunday edit
Fourth Monday edit
Last Wednesday edit
Last weekday edit
Fixed Gregorian edit
- September 1
- Anniversary of the Start of the Armed Struggle (Eritrea)
- Constitution Day (Slovakia)
- Disaster Prevention Day (Japan)
- Emma Nutt Day (International observance)
- First day of school in many countries in Asia, Europe and the Americas.
- Flag Day (Honduras)
- Independence Day (Uzbekistan)
- Journalist Day (Taiwan)
- Knowledge Day (Russia, Ukraine and Armenia)
- National Cherry Popover Day (United States)
- Random Acts of Kindness Day (New Zealand)
- Start of National Arbor Week (South Africa), September 1–7
- Veteran's Day (Poland)
- Teachers' Day (Singapore)
- Wattle Day (Australia)
- September 2
- September 3
- China's victory over Japan commemoration related observances:
- Feast of San Marino and the Republic (Republic of San Marino)
- Flag Day (Australia)
- Independence Day (Qatar)
- Levy Mwanawasa Day (Zambia)
- Memorial Day (Tunisia)
- Merchant Navy Remembrance Day (Canada)
- Merchant Navy (United Kingdom)
- National Welsh Rarebit Day (United States)
- Tokehega Day (Tokelau, New Zealand)
- September 4
- September 5
- September 6
- September 7
- September 8
- Day of the Battle of Borodino (Russia)
- Feast Day of Our Lady of Meritxell (Andorra)
- Independence Day (North Macedonia)
- International Literacy Day
- Martyrs' Day (Afghanistan) (date may fall on September 9, follows a non-Gregorian calendar)
- National day (Andorra)
- Nativity of Mary (Roman Catholic Church), (Anglo-Catholicism)
- Victory Day (Pakistan)
- Victory Day (Malta)
- World Physical Therapy Day
- September 9
- Armored Forces Day (Ukraine)
- California Admission Day (California, United States)
- Children's Day (Costa Rica)
- Chrysanthemum Day (Japan)
- Day of the Victims of Holocaust and of Racial Violence (Slovakia)
- Emergency Services Day (United Kingdom)
- Independence Day or Republic Day (North Korea)
- Independence Day (Tajikistan) from USSR in 1991.
- Martyrs' Day (Afghanistan) (date may fall on September 8, follows a non-Gregorian calendar)
- National Steak Au Poivre Day (United States)
- Remembrance for Herman the Cheruscan (The Troth)
- Wienerschnitzel Day (United States)
- Wonderful Weirdos Day
- September 10
- September 11
- Battle of Tendra Day (Russia)
- Death Anniversary of Quaid-e-Azam Muhammad Ali Jinnah, a former holiday. (Pakistan)
- Emergency Number Day (United States)
- Enkutatash falls on this day if it is not a leap year.(Ethiopia, Rastafari)
- National Day of Catalonia (Catalonia)
- National Hot Cross Bun Day (United States)
- Nayrouz (Coptic Orthodox Church)
- Patriot Day (United States)
- Remember Freedom Day
- Teachers' Day (Argentina)
- September 12
- Most Holy Name of the Blessed Virgin Mary
- Day of Conception (Russia)
- Day of the Programmer, during a leap year. (International)
- Defenders Day (Maryland. (United States)
- Enkutatash falls on this day if it is a leap year. (Ethiopia, Rastafari)
- Mindfulness Day
- National Chocolate Milkshake Day (United States)
- National Day (Cape Verde)
- National Day of Encouragement (United States)
- Saragarhi Day (Sikhism) (this day or nearest weekday, 2015 date: September 11)
- September 13
- September 14
- Children's Day (Nepal) (celebrated on the 15th on leap years)
- Engineer's Day (Romania)
- Feast of the Cross (Christianity)
- Hindi Diwas (Hindi-speaking regions)
- Mobilized Servicemen Day (Ukraine)
- National Cream Filled Donut Day (United States)
- National Eat a Hoagie Day (United States)
- San Jacinto Day (Nicaragua)
- September 15
- Battle of Britain Day (United Kingdom)
- Children's Day (Nepal) (leap years only)
- Engineer's Day (India)
- Free Money Day (International)
- Independence Day (Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica)
- International Day of Democracy (International)
- Knowledge Day (Azerbaijan)
- National Crème de Menthe Day (United States)
- National Double Cheeseburger Day (United States)
- National Linguine Day (United States)
- National Cheese Toast Day (United States)
- Patriotic Day (Guatemala)
- Restoration of Primorska to the Motherland Day (Slovenia)
- Silpa Bhirasri Day (Thailand).
- World Lymphoma Awareness Day
- The beginning of National Hispanic Heritage Month, celebrated until October 15 (United States)
- September 16
- Grito de Dolores (Mexico)
- Independence Day (Papua New Guinea), celebrates the independence of Papua New Guinea from Australia in 1975.
- International Day for the Preservation of the Ozone Layer
- Malaysian Armed Forces Day (Malaysia)
- Malaysia Day (Malaysia, Singapore)
- Martyrs' Day (Libya)
- Heroes' Day (Saint Kitts and Nevis)
- National Cinnamon Raisin Toast Day (United States)
- National Guacamole Day (United States)
- Stay Away from Seattle Day
- September 17
- Australian Citizenship Day
- Constitution Day (United States) (observed on the previous Friday if it falls on a Saturday, the following Monday if on a Sunday)
- Start of Constitution Week, runs from September 17–23
- Heroes' Day (Angola)
- Marathwada Liberation Day (India)
- National Apple Dumpling Day (United States)
- National Monte Cristo Sandwich Day (United States)
- Operation Market Garden Anniversary is still remembered with parachuting and dedications on this day. (Netherlands)
- Teachers' Day (Honduras)
- Von Steuben Day. (United States), weekend of the week of September 17.
- September 18
- September 19
- September 20
- September 21
- Arbor Day (Brazil)
- Commemoration of the Declaration of Martial Law (Philippines)
- Customs Service Day (Poland)
- Founder's Day and National Volunteer Day (Ghana)
- Independence Day, celebrates the independence of Armenia from the Soviet Union in 1991.
- Independence Day, celebrates the independence of Belize from the United Kingdom in 1981.
- Independence Day, celebrates the independence of Malta from the United Kingdom in 1964.
- International Day of Peace (International)
- National Pecan Cookie Day (United States)
- Acknowledgement of Earth, Wind, & Fire's "September"
- Student's Day (Bolivia)
- Victory over the Golden Horde in the Battle of Kulikovo (Russia)
- September 22
- American Business Women's Day (United States)
- Dear Diary Day
- Hobbit Day, the containing week is celebrated as Tolkien Week. (American Tolkien Society)
- Independence Day, celebrates the independence of Bulgaria from the Ottoman Empire in 1908.
- Independence Day, celebrates the independence of Mali from France in 1960.
- OneWebDay, an annual day of Internet celebration and awareness, started in 2006.
- Resistance Fighting Day (Estonia)
- World Car-Free Day
- September 23
- September 24
- September 25
- September 26
- Day of the National Flag (Ecuador)
- Dominion Day (New Zealand)
- European Day of Languages (European Union)
- Johnny Appleseed Day (United States)
- National Better Breakfast Day (United States)
- National Dumpling Day (United States)
- National Good Neighbor Day (United States)
- National Pancake Day (United States)
- Revolution Day (Yemen)
- September 27
- Consumación de la Independencia (Mexico)
- French Community Holiday (French community of Belgium)
- Meskel (Ethiopian and Eritrean Orthodox Church, following Julian calendar, September 28 on leap years)
- National Chocolate Milk Day (United States)
- National Corned Beef Hash Day (United States)
- National Gay Men's HIV/AIDS Awareness Day (United States)
- Polish Underground State's Day (Poland)
- World Tourism Day
- September 28
- Ask a Stupid Question Day (United States)
- Czech Statehood Day (Czech Republic)
- Family Day – A Day to Eat Dinner with Your Children (United States)
- Fish Tank Floorshow Night
- Freedom from Hunger Day
- International Right to Know Day
- Meskel (Ethiopian and Eritrean Orthodox Church, September 28 on leap years only, all other years is September 27)
- National Day of Awareness and Unity against Child Pornography (Philippines)
- Teachers' Day (Taiwan and Chinese-Filipino schools in the Philippines)
- World Rabies Day
- September 29
- Feast of the Archangels Michael, Gabriel, and Raphael.
- National Biscotti Day (United States)
- National Coffee Day (multiple countries, see article)
- Inventors' Day (Argentina)
- Michaelmas One of the four quarter days in the Irish calendar. (England and Ireland)
- Victory of Boquerón Day (Paraguay)
- World Heart Day
- September 30
- Agricultural Reform (Nationalization) Day (São Tomé and Príncipe)
- Birth of Morelos (Mexico)
- Blasphemy Day (United States, Canada, other countries)
- Boy's Day (Poland)
- Independence Day (Botswana)
- International Translation Day (International Federation of Translators)
- National Hot Mulled Cider Day (United States)
- Recovery Day (Canada)
- Orange Shirt Day (Canada)
- Office, Met. "Met Office: Changing seasons". webarchive.nationalarchives.gov.uk. Archived from the original on 2009-02-25.
- 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.
- public domain: Chisholm, Hugh, ed. (1911). "September". Encyclopædia Britannica. Vol. 24 (11th ed.). Cambridge University Press. p. 653. One or more of the preceding sentences incorporates text from a publication now in the
- "The most common birthday is around the corner. Here's where yours falls on the list". USA TODAY. Retrieved 2023-09-09.
- Specktor, Brandon (2020-09-17). "Why September Is the Most Popular Month for Birthdays". Reader's Digest. Retrieved 2023-09-09.
- "Happy birthday to you and you and you: Why Sept. 9 is the most common birthday". TODAY.com. 2023-09-08. Retrieved 2023-09-09.
- SHG Resources. "SHGresources.com". SHGresources.com. Archived from the original on 2013-06-16. Retrieved 2013-08-22.
- "Flowerstower.com". Archived from the original on February 24, 2013. Retrieved 2013-08-22.
- The Earth passes the junction of the signs at 13:30 UT/GMT September 22, 2020, and will pass it again at 19:21 UT/GMT September 22, 2021.
- "Astrology Calendar", yourzodiacsign. Signs in UT/GMT for 1950–2030.
- "Cancer Awareness Month :: Society of Gynecologic Nurse Oncologists". www.sgno.org.
- "September Is Leukemia and Lymphoma Awareness Month" (PDF). Archived from the original (PDF) on 2015-09-05. Retrieved 2016-08-19.
- Baunfire.com, Spark CMS by. "September Is Thyroid Cancer Awareness Month – ThyCa: Thyroid Cancer Survivors' Association, Inc". www.thyca.org.
- "Promote National Suicide Prevention Month". suicidepreventionlifeline.org. Retrieved 2019-11-25.
- "Fruit & Veg Month - Healthy Kids".
- "Food Days, Weeks, Months – September". UNL Food. University of Nebraska–Lincoln.
- Goldstein, Darra (2011). "National Turkey Day". Gastronomica. 11 (4): iii–iv. doi:10.1525/gfc.2012.11.4.iii.
- "September is Hydrocephalus Awareness Month! Here's What You Can Do…". Hydrocephalus Association. Retrieved 29 July 2016.
- "California Wine Month – California Wines". www.discovercaliforniawines.com. Archived from the original on 2018-11-27. Retrieved 2016-08-20.
- "September Monthly Observations". 4 January 2016.
- "Home » te Wiki o te Reo Māori". Archived from the original on 2020-02-06. Retrieved 2020-02-05.