What Month Is September? Number, Etymology & Awareness Months

Ever looked at a calendar and wondered why September, whose name clearly echoes “seven,” is the ninth month? You’re not alone. This article unpacks that ancient riddle, traces the Roman calendar reforms that shuffled the months, and also covers what September is known for today — from awareness campaigns to zodiac signs.

Current month number: 9 (Gregorian calendar) ·
Latin etymology (septem): Means ‘seven’ ·
Original Roman position: 7th month ·
Common question: ‘What month is September?’: 9th month ·
Days in September: 30 ·
Roman calendar added months: January and February

Ten key facts show both the month’s fixed features and the historical confusion behind the name.

The pattern is clear: September’s fixed calendar attributes are stable; its name is a fossil of an older system.

Is September the 9th month of the year?

Yes, September is the ninth month of the modern Gregorian calendar. It has 30 days and falls between August and October. The confusion arises because the name suggests “seven” – a clue that points back to the Roman calendar.

• September is the 9th month in the Gregorian calendar (WebExhibits)
• It has 30 days, confirmed by the nursery rhyme “Thirty days have September” (Wikipedia)

Why this matters: The name-number mismatch is not a mistake – it’s a historical fossil. The Romans never renamed the months after adding new ones, so September kept its “seventh” label even after it moved to ninth.

Why is September the ninth month when it means seven?

The Roman calendar before 153 BCE

• The earliest Roman calendar had 10 months and 304 days, starting in March (WebExhibits)
• September was literally the seventh month (Latin: septem = seven) (Wikipedia)
• The 10 months were: Martius, Aprilis, Maius, Junius, Quintilis, Sextilis, September, October, November, December (WebExhibits)

When January and February were added

• Around 713 BCE (tradition) King Numa Pompilius added January and February, making a 12-month year of 354 days (WebExhibits)
• September became the 9th month, but its name was never changed (Wikipedia)
• The addition may have been gradual; the exact chronology is debated (WebExhibits)

The shift from March as the first month

• In 153 BCE the Roman consular year began on January 1, cementing January as the official first month (Wikipedia)
• The Julian (45 BCE) and Gregorian (1582) reforms kept the 12-month order (WebExhibits)

The catch: The Romans valued tradition over system consistency. Rather than rename the displaced months, they let September keep its original number-name – a decision that still puzzles learners today.

“September comes from the Latin septem, meaning ‘seven’ – the month was originally the seventh in the Roman calendar.”

Wikipedia, free encyclopedia

What awareness month is September?

Several causes and observances fill September’s calendar. The most commonly cited are National Library Card Sign-up Month, National Potato Month, and Self-care Awareness Month.

• National Library Card Sign-up Month is promoted by the American Library Association (Bill Petro)
• National Potato Month celebrates the potato harvest (Bill Petro)
• Self-care Awareness Month encourages mental health practices (WebExhibits) – general awareness

What this means: September is a month with a dual identity – historically a placeholder from the Roman system, and now a canvas for modern awareness campaigns.

Is September 9 a special day?

September 9 is observed as several national and international days. Notably, the United States celebrates National Teddy Bear Day on this date.

• National Teddy Bear Day (US) occurs annually on September 9 (Bill Petro)
• Other observances vary by country and cause (WebExhibits)

The takeaway: September 9 is not a major holiday but marks a lighthearted celebration that adds character to the month.

What month is September known for?

September is widely known as the gateway to autumn in the Northern Hemisphere, and it brings two zodiac signs and the autumnal equinox.

• Meteorological autumn begins September 1 (Maria Donovan)
• Zodiac: Virgo (until Sep 22) and Libra (from Sep 23) (Bill Petro)
• Autumnal equinox around September 22–23 (Maria Donovan)
• The Anglo-Saxons called it Gerstmonath (barley month); the Swiss call it Herbstmonat (harvest month) (Bill Petro)

“The Swiss call September Herbstmonat, meaning harvest month – a reminder of its agricultural roots.”

Bill Petro, historian

The pattern: September is a transition month – from summer to autumn, from Virgo to Libra, and from growth to harvest.

What did the Romans call May?

The Romans called May Maius, after the goddess Maia.

• Maius was the third month in the pre-Julian calendar (WebExhibits)
• Maia was an earth goddess of growth and spring (Wikipedia)

Why this matters: May’s name follows the same pattern as September – rooted in Roman deities and numbers, with no adjustment after the calendar reshuffle.

Is April 30 or 31 days?

April has 30 days, fitting the classic mnemonic.

• “Thirty days have September, April, June, and November” confirms April’s length (Wikipedia)
• This rhyme has been cited as early as the 15th century (WebExhibits)

The trade-off: Month-length rhymes are handy, but they rely on historical convention rather than logic – just like September’s name-number mismatch.

“The Roman calendar originally had 10 months and about 304 days, leaving roughly 61 winter days unaccounted.”

WebExhibits, online museum of science

Timeline: September through Roman and Gregorian history

1. c. 753 BCE – Traditional founding of Rome; early calendar has 10 months (WebExhibits)
2. c. 713 BCE – Numa Pompilius adds January and February; September becomes 9th (WebExhibits)
3. 153 BCE – Consular year now starts January 1; January is official first month (Wikipedia)
4. 45 BCE – Julian calendar reform; September retains 9th position (Wikipedia)
5. 1582 – Gregorian calendar introduced; September stays 9th (WebExhibits)
6. 2026 – Modern awareness months published (e.g., Library Card Sign-up Month) (Bill Petro)

The timeline shows that the Roman calendar evolved over centuries, with September’s position fixed by the addition of January and February.

Confirmed and unclear facts

For students of calendar history, the implication is clear: don’t trust the names – trust the historical reforms that moved September from seventh to ninth. The Roman naming system is a fossil that preserves a calendar that no longer exists.

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For a deeper look at how September got its name and its cultural significance, see Septembers calendar history and culture.

Frequently asked questions