What Is an Equinox?
An equinox is the moment the Sun crosses directly over the celestial equator: an imaginary projection of Earth’s equator into space. Equinoxes occur twice a year, and on these days, daylight and nighttime hours are approximately equal in length. In most Northern Hemisphere cultures, the equinoxes mark the start of spring and fall.
When Is the Fall Equinox in 2026?
The fall equinox (also called the September equinox or autumnal equinox) occurs around September 20 each year, with slight variation due to the Gregorian calendar’s leap year cycle. In 2026, the precise moment the Sun crosses the celestial equator falls on Tuesday, September 22, at 5:05pm MST.
What to Watch for in the Sky
On the morning of the equinox, watch for the Sun rising due east on the horizon, marking the shift from summer to fall. That evening, the Sun sets due west. In the weeks that follow, you’ll notice the Sun’s arc growing lower in the sky with each sunrise and sunset as the Northern Hemisphere moves toward winter, and the Sun continues its path farther south along the horizon.
