What Is Fall Equinox 2025. The first day of autumn often called fall (september equinox or autumnal equinox) is when the sun shines directly on the celestial equator passing from north to. Noaa's goes east satellite captured the moment of autumnal equinox from space on sept 23, 2019.(image credit:
The autumnal equinox (as well as spring equinox) is the moment when neither of the earthโs hemispheres is inclined towards or away from the sun. The first day of fall in 2025 arrives with the fall equinox on sunday, september 22, 2025, at 8:44 a.m.
