The September equinox arrives on September 23, 2015 at 8:21 UTC. Although the equinox happens at the same moment worldwide, your clock times will depend on your time zone. For California, this equinox comes at 1:21 a.m. PDT.
In the Northern Hemisphere, the sun is rising later now, and nightfall comes sooner. This is our autumn equinox, when the days are getting shorter in the Northern Hemisphere. At this equinox, day and night are approximately equal in length. For us in the Northern Hemisphere, people are enjoying the cooler days of autumn even as preparations for winter are underway. South of the equator, spring begins. Learn more about this equinox by following the links below: