About Autumn Equinox (September Equinox)
The September equinox — the astronomical first day of autumn in the Northern Hemisphere — falls around September 22–23, when the Sun crosses the celestial equator heading south. From this moment, northern nights grow longer than days until the December solstice. The countdown above targets the next one.
Cultures mark the moment everywhere: it anchors the Mid-Autumn Festival season in East Asia, Japan observes the equinox as a public holiday (Higan, a time for honoring ancestors), and harvest festivals across Europe trace back to this turning point. For the Southern Hemisphere, the same instant launches spring.
The equinox is set by astronomy, not the calendar, so it lands on September 22 or 23 (very occasionally September 21 or 24) depending on the year and your timezone — the countdown above pinpoints the exact moment and rolls on to the next equinox once it passes. Add it to your own page to mark the first day of fall, or explore more astronomy countdowns like the solstices and eclipses.
Upcoming dates
| 2027 | Thursday, September 23, 2027next |
| 2028 | Friday, September 22, 2028 |
| 2029 | Saturday, September 22, 2029 |
| 2030 | Sunday, September 22, 2030 |
FAQ
When is the autumn equinox 2026?
Autumn Equinox (September Equinox) is on Thursday, September 23, 2027. That is 347 days from today. See the upcoming-dates table above for each year's exact date (September 22 or 23).
What happens at the equinox?
The Sun crosses the celestial equator — day and night are nearly equal worldwide, and the hemispheres trade seasons.
Why is it called an equinox?
The word comes from the Latin for "equal night": near the equinox, day and night are close to equal length across most of the world.
Is the equinox a holiday anywhere?
Japan marks Autumnal Equinox Day as a national holiday — a traditional time for family graves and remembrance.