Equinox

There are two days each year where the day and night are of equal length. For eons, people have used these says to mark beginnings and endings in their year. These days are called an "Equinox".

In the autumn, on either September 22nd or 23rd, we observe the Autumnal Equinox (in the Northern Hemisphere.
In the Southern Hemisphere, it is celebrated on March 20th or 21st).

From this point on, each day will grow shorter, each night longer. The air will turn crisper, the wind a little more brisk. The leaves will turn, and the animals that will be wintering with us get busy with their own preparations for the coming winter.