when does fall officially start

The official start of fall (astronomical fall) in 2025 is on Monday, September 22, 2025. This corresponds to the autumnal equinox, the moment when the Sun crosses the equator and day and night are approximately equal in length. The specific time for this equinox in 2025 is 2:19 p.m. EDT (Eastern Daylight Time) in the U.S. Northern Hemisphere residents generally recognize this as the official start of fall. Meteorologically, fall starts earlier on September 1, but the official astronomical start is tied to the equinox date around September 22 or 23 each year.