Autumnal Equinox Day 2024. Autumnal equinox, two moments in the year when the sun is exactly above the equator and day and night are of equal length; In other words, on the day of the autumnal equinox, the day is almost equal to night, while the duration of daylight hours decreases with each subsequent day.

More change comes on september 22, which is the date of the autumn equinox as well as the. 23, it’s really just a moment in time — to be.