Fall Equinox 2025 Date And Time In Usa. The first day of autumn is in 2025 on september 22 (according to the astronomical definition). Autumn equinox 2025 (beginning of astronomical autumn) on the day of the autumn (september) equinox, the sun, moving along the ecliptic, crosses the celestial equator, moving from the.
United states 2025 holiday calendar with all major holidays and observances. It is also called the autumnal equinox, fall equinox or the beginning of autumn.