Sunset Autumn Equinox 2025 Usa. Autumnal equinox on sunday, september 22, 2025. The first day of autumn often called fall (september equinox or autumnal equinox) is when the sun shines directly on the celestial.
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. 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.