Fall

When does Fall begin?

The first day of Fall begins on September 22 or 23. On the equinox, the sun rises directly in the east and sets directly in the west. This is true for both the fall and spring equinoxes. So on two days of the year you can find the exact cardinal directions of East and West by using the sun.

What is the equinox?

The autumnal equinox for the northern hemisphere is the vernal equinox for the southern hemisphere. Another way to say this is that when fall begins for the northern hemisphere, spring begins for the southern hemisphere.

Characteristics of Fall

The leaves contain chemicals with yellow and orange colors. You don’t see those colors in summer because there is so much green chlorophyll in the leaves hiding the other colors. As winter approaches, the short days don’t provide enough sunlight for the trees to make their food, so the trees live off the food they stored during summer and the trees slow down their food making, in which the green chlorophyll disappears from the leaves.

Why does Fall happen?

Often people think that our temperatures get cooler in autumn because the earth moves farther from the sun. But this is not true. What actually changes is not the distance of the earth to the sun, but the angle of the sun’s rays on the earth. With less and less direct sunlight on the top half, the days here get shorter and temperatures get colder as winter nears. Those shorter days and cooler temperatures act as a signal to the trees and plants around us to get ready for winter.