The first day of fall in 2025 is on Monday, September 22, at 2:19 p.m. This marks the fall equinox, the astronomical start of autumn in the Northern Hemisphere. On this day, day and night are approximately equal in length, and from this point forward, days gradually become shorter until the winter solstice. This date is typical for the fall equinox, which usually falls on September 22 or 23, but can occasionally be as early as September 21 or as late as September 24.
