Autumn Equinox 2024 Countdown Timer. An equinox is one of two days in the year when the sun crosses the equator and day and night become equal in length. Noaa's goes east satellite captured the moment of autumnal equinox from space on sept 23, 2019.(image credit:

The autumn equinox is sometimes referred to as the september equinox. Edt (12:44 utc), according to the national weather service.