Autumn Equinox 2025 Est Time Change. The first day of autumn often called fall (september equinox or autumnal equinox) is when the sun shines directly on the celestial equator passing from north to south and the length of day and night are almost the same. The sun entries into the 4 cardinal signs (aries, cancer, libra, capricorn) mark the equinoxes and solstices:

Monday, sep 22 2:19 pm edt. If daylight saving time is in effect, add one hour to the times listed.