The September Equinox ~ Time and date.com
There are 2 equinoxes every year – in September and March – when the sun shines directly on the equator and the length of day and night is nearly equal.
Opposite Sides & Seasons
In the Southern Hemisphere, it’s known as the Vernal (spring) equinox.
Equinox Local Time & Date
September Equinox in Preston, England, United Kingdom was on
Thursday, 22 September 2016, 15:21 BST (Change city)
September Equinox in Universal Coordinated Time was on
Thursday, 22 September 2016, 14:21 UTC
- Local times for September Equinox 2016 worldwide
- Sunrise, sunset and day length around September Equinox 2016
- Day and Night map for September Equinox 2016
- Equinoxes and solstices from 2000–2049
Sun Crosses Celestial Equator
The September equinox occurs the moment the Sun crosses the celestial equator – the imaginary line in the sky above Earth’s Equator – from north to south. This happens either on September 22, 23, or 24 every year.
Earth’s Axial Tilt
Earth’s axis is tilted at an angle of about 23.4° in relation to the ecliptic, the imaginary plane created by 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 2 equinoxes, the tilt of Earth’s axis is perpendicular to the Sun’s rays, like the illustrations show.
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 holidays and festivals around the September equinox.
The Snake of Sunlight
A famous ancient equinox celebration was the Mayan sacrificial ritual by the main pyramid at Chichen Itza, Mexico.
The pyramid, known as El Castillo, has 4 staircases running from the top to the bottom of the pyramid’s faces, notorious for the bloody human sacrifices that used to take place here. The staircases are built at a carefully calculated angle which makes it look like an enormous snake of sunlight slithers down the stairs on the day of the equinox.
Equinox sun rises due east, sets due west ~ Bruce McClure, TONIGHT | September 22, 2016.
The September 2016 equinox happens on September 22 at 1421 UTC, which translates to 9:21 a.m. Central Daylight Time for us in the central U.S. Translate to your time zone. So as you read this, the exact moment of the equinox might or might not already have happened for you. But maybe it’s not too late for you to catch the equinox sunset?
It’s often said that – at each equinox – the sun rises due east and sets due west. And that’s true. But why? How can you conceptualize this?
First you need to know this. An equinox occurs when the sun crosses the celestial equator. No matter where you are on Earth, the celestial equator intersects your horizon at due east and due west. See the diagram above to try to visualize that.
At its highest point in your sky, the celestial equator appears high or low, depending on your latitude. The imaginary celestial equator is a great circle dividing the imaginary celestial sphere into its northern and southern hemispheres, so, from the equator, it’s directly overhead, for example, wrapping the sky directly above Earth’s equator.
For purposes of today’s visualization, though, the height of the celestial equator in your sky doesn’t matter. What matters are these two things. One, the sun is on the celestial equator at the equinox. Two, the celestial equator intersects your horizon at points due east and due west.
Voila. The sun rises due east and sets due west on the day of the equinox, as seen from around the globe.
This fact – the sun rising and setting due east and west at every equinox – makes the day of an equinox a good day for finding due east and due west from your yard or other favorite site for watching the sky.
Just go outside around sunset or sunrise and notice the location of the sun on the horizon with respect to familiar landmarks. If you do this, you’ll be able to use those landmarks to find those cardinal directions in the weeks and months ahead, long after Earth has moved on in its orbit around the sun, carrying the sunrise and sunset points southward or northward.
Now let’s think about what an equinox really is. It’s an event that happens on the imaginary dome of Earth’s sky, but each equinox also represents a real point on Earth’s orbit. What happens at every equinox is very real – as real as the sun’s passage across the sky each day and as real as the change of the seasons.
Our ancestors didn’t understand the equinoxes as events that occur in the course of Earth’s yearly orbit around the sun. But if they were observant – and many were very observant indeed – they surely marked today as being midway between the sun’s lowest path across the sky in winter and highest path across the sky in summer.
And that’s where we are, in orbit, at this equinox.
We’re midway between the two extremes of the sun’s path in your sky.
Bottom line: The 2016 September equinox comes on September 22 at 1421 UTC – or 9:21 a.m. Central Daylight Time for us in the central U.S. At each equinox, the sun rises due east and sets due west. The diagrams and explanations in this post are meant to help you visualize that.