For the second time in 2025, an incredible astronomical event is about to change the seasons on Earth.
The September equinox is almost upon us, with autumn about to begin in the Northern Hemisphere, and spring about to commence in the Southern Hemisphere.
Equinoxes occur twice a year, with daylight and darkness being about the same length in both the Southern and Northern Hemispheres. This phenomenon's name comes from the Latin words "aequus" (equal) and "nox" (night).
In 2025, the autumn, or fall, equinox occurs at 2:19 p.m. EDT (18:19 UTC) on September 22 in the Northern Hemisphere. Because equinoxes are global events governed by Earth's tilt relative to the sun, the September equinox occurs at the same moment all over the world.
Spring will return to the Northern Hemisphere with the spring, or vernal, equinox on March 20, 2026.
