The Autumnal Equinox in September ushers in a change of season. It is observed annually when the sun can be seen directly overhead along the equator. The day marks the end of summer and beginning of fall in the Northern Hemisphere.
- The autumn equinox is one of two days when all points on Earth except the polar regions see the sunrise and set at due east and due west. With few exceptions, all latitudes see almost precisely 12 hours of daylight and 12 of darkness.
- The Equinox that occurs in September is Vernal (spring) equinox of Southern Hemisphere and the Autumnal (fall) Equinox of the Northern Hemisphere
- The date of an equinox is not fixed due to the earth’s elliptical orbit of the sun.
- The equinox happens at the same time around the world.
- The autumnal equinox marks the change of seasons from summer to fall in the northern hemisphere and the change of winter to spring in the southern hemisphere.
- The days get shorter following the autumnal equinox. They continue to shorten until December’s winter solstice. Winter solstice marks the shortest day of the year, and then they start to become a little longer.
- In astrology the autumnal equinox marks the time when the sun enters the sign of Libra. Libra is the sign of balances scales.
- The full moon that falls near the autumnal equinox is referred to as the harvest Moon. It is so bright that farmers are able to work much later traditionally.
- The autumnal equinox is celebrated in China with a bounty of food, in a festival known as the Mid-Autumn Festival or Moon Festival.
- Animals experience biological changes with the autumnal equinox. The decrease in the amount of daylight is a subtle cue to animals in the Northern Hemisphere to begin preparing for the cold weather by taking in more food, migrating, or finding a place to hibernate.
- To celebrate the autumnal equinox, the Druids gather at Stonehenge in the U.K. to play music, participate in storytelling, and talk about the change of seasons.
- Because it takes the Earth around 365.25 days to orbit the Sun – and why we have a leap year every 4 years – the precise time of the equinoxes varies from year to year, usually happening around six hours later on successive years. On leap years, the date jumps back an entire day
- This year, the sun will rise at 6:44 a.m. EDT on the equinox and will set at 6:51 p.m., giving us ~7 minutes of day over night. Although the sun is perfectly over the equator, we mark sunrises and sunsets at the first and last minute the tip of the disk appears. Also, because of atmospheric refraction, light is bent which makes it appear like the sun is rising or setting earlier.
- The Northern LIghts will be extra visible. With more nighttime darkness, there is simply more hours for viewing; if you are close to the Arctic Circle in the summer, there is too much daylight. But the aurora is also stronger around the equinox because of the planet’s 23.5° tilt and the magnetic field of the solar wind
- There’s a long-standing tale that you can stand eggs up on end during the first day of fall because of the unusual gravitational pull the sun exerts that day. According to the Miami Herald, brooms can be balanced on this special day as well. And, in fact, it is possible to balance eggs (and brooms) on the first day of fall, or on any other day of the year—an astronomer named Frank Ghigo tested it and published a paper in 1987 explaining that certain eggs balance more easily than others.
- Some satellites are vulnerable to disruptions—lots of them orbit around the equator, so when the sun is shining directly on them on the equinox, the unusual amount of solar radiation can lead to slow internet connections and staticky radios, according to National Geographic. These “sun outages” can happen during the days before and after the equinox too, and they usually only last a few minutes.
- Why does pumpkin-spice season have two names, and is one more valid than the other? The word autumn comes from Latin and began being used in England in the 1300s. People also referred to the season as “the fall of the leaves”—the phrase was eventually shortened to fall around the 1600s. A couple of hundred years later, records show that fall had become more popular in the United States and autumn had held the lead in England, but nobody’s sure why.