Which of these signals the beginning of fall?

Answer 1

The vernal equinox is the first day of spring (occurring when the North Pole begins to lean toward the sun). The autumnal equinox is the first day of autumn (occurring when the North Pole leans away from the sun).

Answer 2

Astronomical Spring for the northern hemisphere begins with the March equinox,

and continues until the June solstice.

Astronomical Spring for the Southern Hemisphere begins with the September equinox,

and continues until the December solstice.

There's no such thing as "Spring on Earth", only on 1/2 of it, for 1/2 of the year.

Answer 3

The changing colors of the leaves, cooler temperatures, and the arrival of pumpkin spice flavored foods and drinks are all signals that fall has begun.

Answer 4

vernal equinox

Answer 5

Vernal Equinox

Answer 6

autunmal equinox.

Answer 7

lund