Countdown to
Fall Equinox
Light and dark in balance
Today is Fall Equinox.
325 days until Fall Equinox, on Thursday, September 23, 2027.
Fall Equinox is Thursday, September 23, 2027. Happens the September (autumn) equinox (computed astronomically, in UT).
Twice a year the Sun crosses the celestial equator, standing directly overhead at the equator. The September crossing is the Fall Equinox, the moment the Northern Hemisphere tips away from summer and daylight begins its slow retreat toward winter. It arrives around September 22 or 23 and marks the astronomical start of autumn, one of only two days when day and night fall into rough balance.
Where the date comes from
The word equinox joins the Latin aequus, “equal,” and nox, “night,” a nod to the near-even split of light and dark on this date. The Sun rises almost due east and sets almost due west for nearly everyone on the planet, and the line dividing day from night runs cleanly from pole to pole.
That equality is more poetic than exact. Because the atmosphere bends sunlight and we count the day from the Sun’s upper edge, daytime runs a few minutes longer than night; the true 12-hour split, called the equilux, arrives a few days afterward. The date itself wanders because a year is closer to 365¼ days than 365. The equinox falls about six hours later each common year, and each leap day pulls it back, which is why it lands on the 22nd or 23rd rather than a fixed date.
A timezone note. The equinox is a single instant, and the date shown here is its date in Universal Time (UT). When that instant falls within a few hours of midnight UT, the local calendar date differs: in the Americas it can still be the evening of the previous day, while in East Asia and Australia it can already be the next day. If a printed calendar and this page disagree by a day, that is almost always why.
How it’s marked
For farming cultures the September equinox has long signaled the harvest, and many of its observances still carry that theme. The full moon nearest the equinox is the Harvest Moon, whose bright, early-rising light once let farmers gather crops well after sunset. Modern pagan and Wiccan traditions keep the day as Mabon, a festival of gratitude and balance. In Japan the autumnal equinox is a public holiday, Shubun no Hi, tied to the Buddhist observance of Higan, when families visit and tend ancestral graves.
For most people the turn is quieter: an apple-picking weekend, a shift to heavier food and earlier evenings, the first fire of the season. Some still gather at ancient solar sites. At Chichen Itza the late-day Sun casts a serpent of light and shadow down the great pyramid’s staircase, an alignment that draws crowds around each equinox.
🍂 Fun facts about Fall Equinox
- The name "equinox" means "equal night," but daytime is actually a few minutes longer than night on this date, because the atmosphere bends sunlight and the day is measured from the Sun's upper edge.
- On the equinox the Sun rises almost exactly due east and sets almost exactly due west for nearly everyone on Earth.
- The full moon nearest the September equinox is called the Harvest Moon, named for the bright, early-rising light that once let farmers work past sunset.
- The September equinox begins autumn in the Northern Hemisphere but spring in the Southern Hemisphere, so it is the "fall" equinox for only half the planet.
- Japan observes the autumnal equinox as a national public holiday, Shubun no Hi.
Upcoming Fall Equinox dates
| Date | Days away |
|---|---|
| 325 days | |
| 690 days | |
| 1,055 days | |
| 1,420 days | |
| 1,786 days |
How people mark Fall Equinox
- Harvest feasts
- Mabon gatherings
- Tending ancestral graves in Japan (Higan)
- Sunrise and sunset visits to ancient solar sites
- Apple and pumpkin picking
- Seasonal home decorating
Frequently asked
What day is the Fall Equinox?
The September, or autumnal, equinox falls around September 22 or 23 each year in the Northern Hemisphere. The exact date and time shift slightly from year to year because Earth's orbit does not line up neatly with the 365-day calendar.
Are day and night exactly equal on the equinox?
Almost, but not quite. Although "equinox" means equal night, atmospheric refraction and the Sun's width make daytime a few minutes longer. The day of true 12-hour balance, called the equilux, comes a few days later.
Is the Fall Equinox the same moment everywhere?
Yes. The astronomical instant happens simultaneously around the world, but it marks the start of autumn in the Northern Hemisphere and spring in the Southern Hemisphere.
How is the equinox different from a solstice?
At the equinox the Sun crosses the celestial equator and day and night are roughly equal. The solstices mark the year's longest and shortest days, when the Sun reaches its highest and lowest points at noon.