When Is The First Day Of Fall 2025. Fall begins with the autumnal equinox, monday, september 22, 2025, 2:19. There, the date of the autumnal equinox can change between march.

In 2025, the exact time of the start of fall is at 18:19 uct. The first day of autumn often called fall (september equinox or autumnal equinox) is when the sun shines directly on the celestial equator passing.