When Is The First Day Of Fall 2025 In Az Usa. Autumn 2025 starts on monday, 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. 365 days a calendar at hand!

January 11, 2025, 8:00 pm garrison keillor tonight! The first day of autumn is in 2025 on september 22 (according to the astronomical definition).