September is the 9th month of the year and has 30 days. The name comes from septem, Latin for seven, because September was the seventh month when the Roman year still started in March. For much of the Northern Hemisphere it’s the back-to-school month and the unofficial end of summer.
How many days does September have?
Thirty. It’s one of only four 30-day months, alongside April, June, and November — the ones the old rhyme singles out. The months of the year table lays out the full set.
What season is September?
September turns the season. It usually opens with summer-like weather in the Northern Hemisphere, then the autumn equinox around September 22 — day and night nearly equal — marks the start of astronomical fall. In the Southern Hemisphere the same date begins spring.
What quarter is September in?
September closes the third quarter (Q3). The end of the month is a common reporting and budgeting deadline, and September 30 is the last day of the US federal government’s fiscal year.
September holidays and observances
- Labor Day in the United States and Canada, on the first Monday
- The autumn (or spring) equinox around September 22
- Rosh Hashanah, the Jewish new year, often falls in September
- Hispanic Heritage Month begins on September 15 in the US
September at a glance
The birthstone is sapphire, the traditional flowers are the aster and morning glory, and the zodiac moves from Virgo into Libra around September 23. The month sits between August and October. For the current month, see what month is it.
September by the numbers
| Fact | Value |
|---|---|
| Days in the month | 30 |
| Day of the year on September 1 | 244 (245 in a leap year) |
| Day of the year on September 30 | 273 (274 in a leap year) |
| Share of the year finished by the end of September | about 74.8% |
| Days left in the year after September 30 | 92 |
| September 1, 2026 falls on | Tuesday |
| September 1, 2027 falls on | Wednesday |
Because February 29 comes earlier in the year, every day in September has a day number one higher in a leap year. To find the day number of any date by hand, add up the days in the months before it and then add the date: September 15 is 243 + 15 = 258 in a common year. The day of the year tool works it out for any date.
September 2026 calendar
September 2026 starts on a Tuesday and ends on a Wednesday. Federal holidays (as observed) are in bold.
| Sun | Mon | Tue | Wed | Thu | Fri | Sat |
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | ||
| 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| 13 | 14 | 15 | 16 | 17 | 18 | 19 |
| 20 | 21 | 22 | 23 | 24 | 25 | 26 |
| 27 | 28 | 29 | 30 |
Key dates in September 2026 and 2027
| Date | Day | Event | Note |
|---|---|---|---|
| September 7, 2026 | Monday | Labor Day | federal holiday |
| September 6, 2027 | Monday | Labor Day | federal holiday |
Business days in September
| Month | Weekdays | Federal holidays on weekdays | Business days |
|---|---|---|---|
| September 2026 | 22 | 1 | 21 |
| September 2027 | 22 | 1 | 21 |
Business days here are Monday to Friday minus observed US federal holidays. State holidays and company closures can lower the count further.