Fall Equinox 2024 Day 1. This sunday, the autumnal equinox is upon us, and with it, a shift to shorter days, longer nights and the astronomical start of fall in the northern hemisphere. Here is all you need to know.
In 2024, the autumnal (fall) equinox arrives on sunday, september 22, marking the official first day of fall. Autumnal equinox โ is an astronomical phenomenon, when the sun in its visible motion along the ecliptic crosses the celestial equator.