Fall Equinox 2025 Day Of The Week. The first day of autumn is in 2025 on september 22 (according to the astronomical definition). Equinox means equal day and night (12 hours each).it is a time for balance.
In greek mythology, the fall equinox marks the return of the goddess persephone to the underworld for. It also lists astronomical sunrise and sunset timings on autumnal equinox day.