Autumn Equinox 2025. 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. Equinox means equal day and night (12 hours each).it is a time for balance.
In 2025 the autumnal equinox will occur on 22 september at 18.20 gmt (19.20 bst). 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.