Start Of Autumn 2024 Usa. Autumn 2024 starts on sunday, september 22nd in the northern hemisphere, with daylight time shortening and the leaves begining to fall with the changing tilt of the earth's axis. In 2024, the last day of summer in the northern hemisphere is september 22!.

The official first day of fall, otherwise known as the autumnal equinox, is this. According to the farmer’s almanac, the exact time of the autumnal equinox in the northern hemisphere is 8:.