What is the September Equinox?
Spring in the South
Seasons are opposite on either side of the Equator, so the equinox in September is also known as the Autumnal (fall) equinox in the northern hemisphere. In the Southern Hemisphere, it's known as the Spring (vernal) equinox.
September Equinox in Washington DC, District of Columbia, USA is on
Thursday, September 22, 2016 at 10:21 AM EDT (Change city)
September Equinox in Universal Coordinated Time is on
Thursday, September 22, 2016 at 14:21 UTC
Sun Crosses Celestial Equator
The September equinox occurs the moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth’s Equator – from north to south. This happens either on September 22, 23, or 24 every year.10 Facts About the March Equinox
The Axial Tilt
The Earth's axis is always tilted at an angle of about 23.4° in relation to the ecliptic, the imaginary plane created by the Earth's path around the Sun. On any other day of the year, either the southern hemisphere or the Northern Hemisphere tilts a little towards the Sun. But on the two equinoxes, the tilt of the Earth's axis is perpendicular to the Sun's rays, like the illustration shows.
On the equinox, night and day are nearly exactly the same length – 12 hours – all over the world. This is the reason it's called an "equinox", derived from Latin, meaning "equal night". However, even if this is widely accepted, it isn't entirely true. In reality equinoxes don't have exactly 12 hours of daylight
Traditions and Folklore
In the Northern Hemisphere, the September equinox marks the start of fall (autumn). Many cultures and religions celebrate or observe holidays and festivals around the September equinox.