The September Equinox is one of two days in the calendar year when day almost equal the night hours. In the northern hemisphere it is also the first day of Autumn or Fall (Gregorian calendar), called the Autumnal Equinox. (In the southern hemisphere it is the first day of Spring.)

The Autumnal Equinox marks when green things begin to shed, when growth which was young in the spring has reached maturity. Animals prepare for winter, tree leaves turn colors, and the air takes a chill. In most cultures this a time for harvest and taking stock of life's fragility. It is a time when people begin noticing the waning hours of daylight in anticipation of the winter. Since this time of year is one of the most temperate, it is also a good time to reflect on the meaning of life.

In every culture the Autumnal Equinox signals the return of weather that favors slowing down, introspection, and conservation. Many cultures celebrate the harvest as a means to defeat the starvation brought on by winter. It is also a time closely associated with the dead. Though the dead do not return to life nor walk the earth this time of the year, it is well to remember or memorialize those who are no longer with us. For freethinkers the Autumnal Equinox is a great time to celebrate the lives of those who contributed to the freethought movement. It is also a perfect day to contemplate your own thoughts on the meaning you invest in life, and share those thoughts with others.