First Day Of Meteorological Fall 2025. Winter begins with the winter solstice, saturday, december 21, 2024, 4:21 a.m. Many people consider the september equinox to be the official start of autumn, but for meteorologists, the new season kicks off weeks before the astronomical event.

In the northern hemisphere the dates of the meteorological autumn extend from september 1 to november 30 (september, october and november). The first day of fall in 2024 arrives with the fall equinox on sunday, september 22, 2024, at 8:44 a.m.