Autumn Equinox Southern Hemisphere 2024 Calendar. In the northern hemisphere, the autumnal equinox takes place on september 22, 2024, at 12:44 gmt (08:44 a.m. 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,.

Cdt) on september 22, 2024. In 2024, the autumnal (fall) equinox arrives on sunday, september 22, marking the official first day of fall.