Fall Equinox 2024 Celebrations In Usa. We celebrate the september equinox as the first day of autumn for the northern hemisphere, and the first day of spring for the southern hemisphere. 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,.
But are day and night actually equal length. Twice a year, around march 20 or 21 and sept.
