Tuesday marks the first day of fall and although the change of seasons is subtle in SoCal, this is an astronomical event that happens when the sun crosses the equator from north to south.
It’s the second time of the year when the tilt of the earths axis and the earths orbit around the sun combine in a way that the axis is inclined neither away from north toward the sun. The other time is the vernal equinox or popularly known as spring.
On the two equinoxes every year, the sun shines directly on the equator and the length of the day and night is nearly the same. Equinox is Latin for equal night. The day length will continue to get shorter through December 21 when Fall comes to an end and winter begins.
Here's a fun fact: the equinoxes are opposite on either side of the equator. In the Northern Hemisphere it’s all about scarves and pumpkin spice, while in the Southern Hemisphere it’s the start of Spring with blooming flowers and warming temperatures.