Everyone has their own associations with Fall.
For some, it’s the leaves turning color.
Others note the first frost (and the end of summer vegetable gardens).
In our household . . . it’s invariably the “low tire pressure” light on our car dashboards that switches on when the overnight temp’s dip close to (or below) freezing.
Cold air contracts, making the tire pressure fall, and tripping the warning light.
P.S.: you know that the warning light (pictured above) isn’t one of our cars because the gas tank is full.