Fall Equinox 2025 Date 4. It is also called the autumnal equinox, fall equinox or the beginning of autumn. The first day of autumn often called fall.

In 2025, the autumnal (fall) equinox arrives on monday, september 22, marking the official first day of fall. Autumnal or fall equinox is a day when the tilt of the earth’s axis causes the sun to shine directly above the equator.