Equinox 2025 Fall. 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. Find out more about equinoxes and solstices.
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. Utc) on september 22, officially marking the beginning of fall in the northern hemisphere and the start of spring in the.