When Is The Fall Equinox 2025. When do the four seasons start in 2025—for spring, summer, fall, and winter? As september 22nd approaches, we find ourselves on the cusp of a celestial event that has captivated humans for millennia:
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,. The autumnal equinox, or the first day of fall in the northern hemisphere takes place every year on september 22nd or september 23rd.