Did You Know…


1. Second Equinox of the Year
The September equinox is on or around September 22, while the first equinox of the year, the March Equinox, takes place on or around March 21 every year.

2. Say Goodbye to Summer…
…in the Northern Hemisphere. Astronomically, the September equinox is the autumnal, or fall, equinox marking the end of summer and the beginning of fall (autumn). The fall season ends on December Solstice, when astronomical winter begins.

Meteorological vs. astronomical Seasons
For meteorologists, on the other hand, fall in the Northern Hemisphere begins about 3 weeks before the September equinox on September 1 and ends on November 30.

3. And Welcome Spring
In the Southern Hemisphere, the September equinox is the vernal (spring) equinox.
The September equinox is also known as the vernal or spring equinox in the Southern Hemisphere and is considered by astronomers as the first day of spring there.

4. A Moment in Time
Equinoxes & solstices local times
Illustration image
The staircases at the main Maya pyramid, El Castillo, at Chichen Itza, Mexico, are built at a carefully calculated angle which makes it look like a snake of sunlight slithers down the stairs the moment the equinox occurs.

Equinoxes are not day-long events, even though many choose to celebrate all day. Instead, they occur at the moment the Sun crosses the celestial equator—the imaginary line in the sky above Earth’s equator.
At this instant, Earth’s rotational axis is neither tilted away from nor towards the Sun.

Earth’s axial tilt is the reason
In 2022, the Sun crosses the celestial equator from north to south on September 23, at 01:03 UTC. Because of time zone differences, the equinox takes place on September 22, 2022 at locations that are at least 1 hour 3 minutes behind UTC. These include cities in the United States, South America, and Canada.

5. The Date Varies
Statue of Pope Gregory XIII Bologna, Italy.
Statue of Pope Gregory XIII Bologna, Italy.

While the September equinox usually occurs on September 22 or 23, it can very rarely fall on September 21 or September 24. A September 21 equinox has not happened for several millennia. However, in the 21st century, it will happen twice—in 2092 and 2096. The last September 24 equinox occurred in 1931, the next one will take place in 2303.
The equinox dates vary because of the difference between how the Gregorian calendar defines a year (365 days) and the time it actually takes for Earth to complete its orbit around the Sun (about 365 and 1/4 days).

This means that each September equinox occurs about 6 hours later than the previous year’s September Equinox. This eventually moves the date by a day.

Note: These dates are based on the time of the equinox in UTC. Due to time zone differences, locations ahead of UTC may celebrate the September equinox a day later, and locations behind UTC may celebrate it a day earlier. Most locations on Earth do not experience equal day and night on September equinox.

Source: Time and Date . com