When Is The Autumnal Equinox 2024. The name equinox comes from the latin aequus (equal). Autumn equinox 2024 (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 northern hemisphere to the southern.
The autumnal equinox (as well as spring equinox) is the moment when neither of the earthโs hemispheres is inclined towards or away from the sun. The fall equinox will occur at exactly 8:44 a.m.