Autumn officially starts with the fall equinox on Sept. 22, 2026

The official start of autumn is scheduled for September 22, 2026. This specific date marks the occurrence of the fall equinox, which aligns perfectly with the first day of the autumn season. Both the fall equinox and the commencement of autumn arrive simultaneously on this day in September. This astronomical event signifies the formal transition into the autumn period, ensuring that the equinox and the seasonal start happen on the same calendar date.