The first day of fall (autumnal equinox) in 2024 is on Sunday, September 22. This marks the moment when the sun is directly above the equator, and day and night are approximately equal in length in the Northern Hemisphere. The autumnal equinox in 2024 occurs specifically at 8:44 AM EDT (Eastern Daylight Time). Meteorologically, fall may be considered to start on September 1, but the astronomical start is the equinox on September 22, 2024, which is the more widely accepted definition for the first day of fall.