Autumn Equinox 2025 Est Date. 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. Sunday, dec 21 10:03 am est.

It is also called the autumnal equinox, fall equinox. Monday, sep 22 2:19 pm edt.