The next equinox is coming up in just under seven hours at the time of this posting, at 2023-09-23 06:50 UTC
(See when the impending southward equinox will be in YOUR timezone!)
Many folks have the impression that the equinox is "when day or night are equal" but actually, an equinox is a moment in time! It's when the sun is directly above the Earth's equator, and happens twice a year.
Above image of the moment of equinox from wikipedia.
The day that day and night are equal is known as the equilux and happens in different places on different days (depending on latitude).
And, if you are close enough to the equator, you NEVER get a day less than 12 hours and a day is ALWAYS at least a few minutes longer than night! This is because of atmospheric refraction.
Speaking of atmospheric refraction, this also causes the sun to be above the horizon at BOTH the north and south poles for a short time before and after an equinox!
According to what I've been able to determine (with this sunrise and sunset calculator) at the south pole, the sun rose September 21 at 03:39 UTC, and the sun will set at the north pole on September 25 09:58 UTC!