Spring equinox 2024: When it is and why it's also called the vernal equinox

Tiffany Acosta
Arizona Republic


Spring is blooming and with it comes the spring equinox. This celestial event occurs annually, marking the moment when the Earth's axis is neither tilted away from nor toward the sun, resulting in nearly equal lengths of day and night across the globe.

This phenomenon symbolizes the transition from winter to spring in the Northern Hemisphere and from summer to autumn in the Southern Hemisphere.

Beyond its astronomical significance, the spring equinox holds cultural, spiritual and metaphorical importance for many people worldwide. Throughout history, cultures have marked this occasion with festivals and ceremonies.

Here is everything you need to know about the spring equinox.

When is the spring equinox 2024?

The spring equinox officially starts at 8:06 p.m. Arizona time on Tuesday, March 19.
What is the difference between spring equinox and vernal equinox?

According to NASA, the terms "spring equinox" and "vernal equinox" refer to the same astronomical event and are used interchangeably. Both terms describe the moment when the sun crosses the celestial equator, moving from south to north.

Why is it called vernal equinox?

The term "vernal equinox" originates from Latin, where "vernal" means spring and "equinox" denotes the equal length of day and night. The term "vernal equinox" specifically emphasizes the seasonal aspect while "spring equinox" is more generic, referring to the equinox that occurs in springtime.
Is spring equinox always March 21?

No. The spring equinox does not always occur on March 21. While March 21 is often cited as the date of the spring equinox, it can occur on March 20 or 21st, depending on the year and time zone, according to Almanac.com. This variation is due to the complexities of Earth's orbit around the Sun and the adjustments made in the calendar system to account for these movements.

What happens at the spring equinox?

The spring equinox marks the moment when the sun crosses the celestial equator, heading northward. On this occasion, day and night are approximately of equal duration all over the Earth, according to the National Weather Service.

The spring equinox is considered the beginning of spring in the Northern Hemisphere. Cultures around the world have celebrated this event for centuries through various rituals, festivals and traditions, often focusing on themes of fertility, growth and the balance between light and dark.

Will spring come early 2024?

Sorry, Punxsutawney Phil, but predicting whether spring will come early in a specific year depends on numerous factors such as weather patterns, atmospheric conditions and regional climate dynamics.

While the spring equinox occurs at a fixed point in time each year, the arrival of warmer temperatures, the blooming of flowers and other signs of spring can vary.


Some years may experience earlier spring due to warmer weather patterns or climate variability, while others may see colder temperatures lingering longer.

The spring equinox typically falls on March 20 or 21, but in a leap year like 2024, when February has an extra day, the equinox may occur a bit earlier.
What are the 4 equinox dates?

Here are the 2024 equinox and solstice dates, according to the National Weather Service:
Spring (vernal) equinox: March 19, 2024, at 9:06 p.m.
Summer solstice: June 20, 2024, at 2:51 p.m.
Autumn equinox: Sept. 22, 2024, at 6:43 a.m.
Winter solstice: Dec. 20, 2024, at 2:20 a.m.

All times are Arizona time.
What does the spring equinox symbolize?

The spring equinox symbolizes renewal and rejuvenation, the transition from darkness to light as nature emerges from the dormancy of winter.

Many cultures observe the spring equinox with festivals and rituals centered around fertility, abundance and the renewal of life, according to the almanac.com.

Ancient monuments such as the Sphinx in Egypt and Angkor Wat in Cambodia align with the equinox, showcasing humanity's historical reverence for this celestial event.

The spring equinox is also regarded as a time for balance, harmony and personal growth.
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Why is it called equinox?

The term "equinox" comes from the Latin words "aequus," meaning equal, and "nox," meaning night. It is called so because during the equinox, day and night are approximately equal in length.

It's a moment of balance and symmetry in the Earth's orbit around the sun, symbolizing the cyclical nature of time and the changing of seasons.

 World Photos

Celebrating spring equinox with Nowruz, a Celtic tradition and other festivals

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This year, spring equinox begins today at 5:24 p.m. ET

CBC News · Posted: Mar 20, 2023 2:42 PM MDT 

The Persian New Year Nowruz, which means new day, marks the official beginning of spring and a brand new year. Here, people celebrate in Akra, in Kurdistan, Iraq, on Monday. (Alaa Al-Marjani/Reuters)

Monday marks the first day of spring in the Northern Hemisphere. During the equinox, the Earth's axis and its orbit line up so that both hemispheres get an equal amount of sunlight.

The spring equinox can land on March 19, 20 or 21, depending on the year. This year, it begins today at 5:24 p.m. ET. Take a look at various ways people are celebrating around the world.

Persian New Year

People carry fire torches while celebrating Nowruz Day, a festival marking the first day of spring and Persian New Year, in the town of Akra near Duhok, in Kurdistan, Iraq, on Monday.

(Alaa Al-Marjani/Reuters)

(Alaa Al-Marjani/Reuters)

The Druid way

Members of the Druid Order take part in a ceremony celebrating the spring equinox at Tower Hill in London on Monday.

(Henry Nicholls/Reuters)

(Henry Nicholls/Reuters)

(Henry Nicholls/Reuters)

In Mexico

The Pyramid of the Moon is seen on the day of the spring equinox as hot air balloons float above the pre-Hispanic city of Teotihuacán on the outskirts of Mexico City on Monday. 

(Henry Romero/Reuters)

A man takes pictures of the hot air balloons flying near the Pyramid of the Sun.

(Claudio Cruz/AFP/Getty Images)

Another view of the balloons above the Pyramid of the Sun.

(Henry Romero/Reuters)

A Celtic tradition

Residents wait to ignite wooden disks during the Schieweschlàwe festival in Offwiller, eastern France, on Feb. 26. The Schieweschlawe festival is a Celtic tradition to drive away evil spirit and celebrates equinox.

(Jean-Francois Badias/The Associated Press)

A man shakes a wooden disk to keep it on fire during the festival.

(Jean-Francois Badias/The Associated Press)

(Jean-Francois Badias/The Associated Press)

Spring backwards? Why next spring will

come earlier than it has in nearly 130 years

A woman holds a branch on a cherry blossom tree in full bloom as a person with her takes photographs, in Vancouver, on Tuesday, April 5, 2022.

(THE CANADIAN PRESS/Darryl Dyck)

Natasha O'Neill
CTVNews.ca Writer
Updated March 20, 2023

Spring is coming to Canada and officially begins March 20 at 5:24 p.m. ET/ 2:24 p.m. PT.

Known as the spring equinox, the day marks the end of winter, and brings hope for warmer weather.

The spring equinox occurs when the sun crosses the equator line going north, resulting in longer and warmer days for those living in the Northern Hemisphere.

On the first day of spring, the sun will be shining equally on both halves of the Earth, Space.com explains.

But next year, spring will come a whole calendar day early, with the first day falling on March 19, for the first time since the 1800s.

WHAT HAPPENS TO EARTH DURING THE SPRING EQUINOX?

The Earth is shifting its elliptical (meaning oval-shaped) orbit, as it "slowly" rotates on its axis, the U.S. Astronomical Applications department website reads.

During winter in Canada, Earth is tilted on its axis diagonally, with the sun's rays hitting the Southern Hemisphere more directly, causing summer, the NASA website says. The opposite tilt occurs in the Northern Hemisphere's summer, bringing warm weather to countries north of the equator.

During spring and fall, the sun is shining equally on both the northern and southern hemispheres.

The Earth takes 365.25 days to orbit the sun, which is rounded down to 365 days -- the length of one year.

WHY IS SPRING A DAY EARLIER IN 2024?

The extra quarter of a day is not counted each year, but instead added up, so that every four years, February gains an extra day to make up those hours.

"Say that July is a warm, summer month where you live. If we never had leap years, all those missing hours would add up into days, weeks and even months," the NASA website says. "Eventually, in a few hundred years, July would actually take place in the cold winter months!"

Next year is one of these leap years, and the existence of Feb. 29 shifts the whole calendar, causing the spring equinox to occur on March 19 instead of March 20.

Leap years are also the reason the spring equinox used to occur on March 21, versus March 20, in the previous century.

The periodic shifting of the calendar due to leap years is the reason the official start of seasons shifts over a couple of days.

The first day of spring is often March 20 or 21, but next year won't be the first time it's fallen on the 19th. It is, however, the first time it's been on that day in over a century.

The most recent March 19 first day of spring was in 1896. Spring will also start on March 19 in 2028, according to time-keeping website TimeandDate.com.

 

SEE

LA REVUE GAUCHE - Left Comment: Search results for VERNAL EQUINOX 

LA REVUE GAUCHE - Left Comment: Search results for SPRING EQUINOX 

LA REVUE GAUCHE - Left Comment: Search results for EQUINOX 

Why the first day of autumn is later than usual this year

Glenn Roberts · Columnist | Posted: a day ago 

An illustration of the March (spring) and September (fall or autumn) equinoxes. During the equinoxes, both hemispheres receive equal amounts of daylight. - NASA/JPL-Caltech

You might be wondering why the autumnal equinox is on Sept. 23 this year – it officially starts at 3:50 a.m. ADT (4:20 a.m. NDT) – and not on the usual date, Sept. 21 or 22.

The date of the autumnal equinox – like the vernal equinox, summer and winter solstices – can vary yearly.

Its date is not determined by the calendar but is an astronomical moment in time when the sun crosses the celestial equator (the plane of the Earth's equator extended out into space), moving from north to south.

While equinoxes and solstices occur at the same moment in time across the globe, due to varying time zones, the actual date of the equinox or solstice may vary, depending on geographical location.

Autumnal equinoxes can occur between Sept. 21-24; in 2024, it's on Sept. 22

Equal day and night

On the date of the autumnal equinox, the sun is directly overhead at local solar time (as seen from Earth's equator).

The word "equinox" comes from the Latin words aequs (meaning "equal") and nox (meaning "night"), referring to equal daylight and nighttime.

There are two equinoxes each year: autumnal and spring here in the Northern Hemisphere. In the Southern Hemisphere, Sept. 23 marks the southern vernal equinox or the beginning of their spring.

On the vernal and autumnal equinoxes, the Earth's axis is neither tilted towards or away from the sun (as it is during the summer and winter solstices in the Northern Hemisphere). The amount of sunlight striking both hemispheres of the Earth's surface is pretty much the same: every latitude across the planet receives approximately the same amount of daylight as it does darkness as the sun is directly over the equator.

Day and night are only relatively equal in length for areas close to the equator; the length of day and night for non-equatorial regions depends on latitude.

For example, on Sept. 23, in Charlottetown, P.E.I., (latitude 46.23824 degrees north), the sun will rise at 7 a.m. and set just after 7:08 p.m., giving a day length of 12 hours, eight minutes, and nine seconds.

On the day of both equinoxes, the sun will rise almost due east and set almost due west, depending on your exact latitude. Charlottetown, on Sept. 23, will see the sunrise at 89 degrees east and set at 271 degrees west.

Decreasing light

Except for tropical regions, most locations in the Northern Hemisphere see a slow but steady decrease in daylight after the summer solstice (the longest day of the year), with the day-to-day differences greatest around the date of the autumnal equinox.

The same is true for the spring equinox, except the daylight period steadily grows longer.

After the autumnal equinox, the daylight period continues to shorten at an ever-decreasing rate until the winter solstice (the shortest period of daylight of the year), when it reaches zero.

Regions closer to the poles experience larger day-to-day differences than those closer to the equator.

Equilux

The moment when daylight and nighttime hours are equal is known as an "equilux," occurring a few days before the spring equinox and after the autumnal equinox in both hemispheres.

For Charlottetown, the equilux is Sept. 25. If you would like to find out when an equilux will occur where you live (you will need to know your approximate latitude), go to timeanddate.com/astronomy/equilux.html.

Astronomy vs. meteorology

The astronomical definition of when seasons begin differs from the meteorological definition.

While astronomical autumn begins Sept. 23, meteorological autumn (which defines the start of the seasons as occurring on the first day of the month that includes the equinox or solstice) occurred Sept. 1.

As the Earth doesn't move at a constant speed in its orbit around the sun, the actual timings of equinoxes and solstices can change each year, meaning the length of astronomical seasons also varies.

On average, the autumnal season in the North Hemisphere lasts about 89.8 days; in the Southern Hemisphere, it's approximately 92.8 days.

Differences

Not all countries use the astronomical definition of when the seasons change.

Australia and New Zealand use the meteorological definition to mark seasons, with spring starting Sept. 1. Some Southeast Asian cultures divide the year into six seasons.

Finland and Sweden base the date of seasons not on a calendar, but on temperature. Seasons within these two countries start and end on different dates, depending on each region's climate.

Global climate change will, no doubt, dramatically alter how these countries determine the start of their seasons.

This week's sky

Mercury (magnitude +2.5, in Leo - the Lion) has emerged from inferior solar conjunction and will reach its highest point in the morning sky 16 degrees above the eastern horizon on Sept. 23, before fading from view as the sun rises.

Venus (magnitude -4.5, in Cancer - the Crab), now at its brightness morning apparition, rises around 3:35 a.m., reaching an altitude of 29 degrees above the eastern horizon, before fading from view around 6:30 a.m.

Saturn (magnitude +0.5, in Aquarius - the Water Bearer) becomes accessible shortly before 8 p.m., 12 degrees above the southeast horizon as darkness falls, reaching a height of 31 degrees above the southern horizon by 11:40 p.m., and remaining visible until about 3:35 a.m. when it drops below 10 degrees above the southwest horizon.

Jupiter (magnitude -2.7, in Aries - the Ram) is visible by about 10 p.m., seven degrees above the eastern horizon, reaching its highest point of 58 degrees in the pre-dawn, southern sky around 4:15 a.m., then becoming lost in the dawn twilight 47 degrees above the southwest horizon by 6:30 a.m.

Mars, two degrees below the western horizon at dusk, is not observable this week.

Comet C/2023 P1 Nishimura reached perihelion (its closest passage of the sun) on Sept. 17 and is too close to the sun to be observed in the western, post-sunset twilight. It will pull away from the sun over the coming weeks, and, although fading in brightness, may still be visible.

Until next week, clear skies.

---

Events:

• Sept. 18 – Venus at greatest brightness in morning sky; mag, -4.5
• Sept. 22 – First Quarter Moon
• Sept. 23 – Autumnal Equinox; start of autumn season in Northern Hemisphere
• Sept. 23 – Mercury at its highest altitude in the morning sky; 16 degrees above the eastern horizon

---

Glenn K. Roberts lives in Stratford, P.E.I., and has been an avid amateur astronomer since he was a small child. He welcomes comments from readers at glennkroberts@gmail.com.

IS THE DAY 12 HOURS LONG ON THE EQUINOX? IT'S COMPLICATED

BY: BOB KING SEPTEMBER 20, 2023  

Denser air near the horizon acts like a lens and refracts (bends) the Sun's bottom half upward into the top, compressing the solar disk into a bean. Refraction also "lifts" the Sun into view at the horizon about 2 minutes before the real Sun arrives there. Both effects increase the amount of daylight we experience at the equinoxes.
Bob King

Astronomical cycles acquaint us with the inevitable. That's what I'm thinking right now as we approach the first official day of fall (spring in the southern hemisphere), also known as the autumnal equinox. At 2:49 a.m. EDT, the Sun will cross the celestial equator going south and won't stop its descent until it bumps into the winter solstice on December 21st.

The celestial equator is a projection of Earth's equator on the sky. On that special day, the Sun will pass directly overhead at noon for residents living along the equator, from Nairobi to Quito to Singapore. At local noon, when the Sun passes overhead, residents won't be able to avoid stepping on their shadows. On the same day at the North and South Poles the Sun scrapes completely around the horizon. And no matter where you live except the poles it rises due east and sets due west.

At both the spring and fall equinoxes, the Earth's axis tilts neither toward nor away from the Sun but sidelong. Day and night momentarily strike a balance, each of them 12 hours long on this day, so neither one of them has the upper hand. That's why we call it the equinox, which literally means "equal night." Right?

Don't believe it. There's more to daylight on the equinox than you might think.

THE SUN'S DISK

Venus, pictured here at dawn on September 14, 2023, is essentially a point source compared the Sun's disk.
Bob King

Even on the equinox, daylight still edges out night for two reasons. First, the Sun is a disk, not a point source. If the Sun were simply a more brilliant version of Venus, all of it would rise in one pop. Instead, sunrise is defined as the moment when the Sun's upper edge breaches the horizon. Since the solar disk is about ½° in diameter, its full disk takes between 2.5 and 3 minutes at mid-latitudes to clear the horizon. Similarly, sunset is the moment the trailing limb finally touches the western horizon. That adds another 2.5 to 3 minutes of sunshine at day's end. The result is a total of approximately 5 to 6 minutes of additional daylight. By the way, this is true for every day of the year, not just on the equinox.

As one approaches the Arctic at the time of the fall equinox, the Sun's angle of ascent becomes shallower and shallower. In Alert, Nunavut, the northernmost continuously inhabited place in the world, it takes more than 16 minutes from the moment of sunrise until the Sun clears the eastern horizon! At the equator — the opposite extreme — the Sun rockets straight up from the due-east horizon and extricates itself in just over 2 minutes.

THE EARTH'S AIR

Adding to the complexity is the fact that Earth has air. Consider atmospheric refraction, in which light rays are bent when they pass from a less dense medium (outer space) into a more dense medium (Earth's atmosphere). A familiar example is the "broken" straw sticking out of a glass of water. Light from the top of the straw travels directly to our eyes, while light from the underwater part is refracted (bent) and travels in a slightly different direction, making it look as if it's fractured.

A pencil in a glass of water looks broken because we see the top part through air and the bottom part through the denser medium of water, which bends or refracts the light in a different direction to our eyes. Refraction effects also magnify the submerged half.
Bob King

As the Sun approaches the horizon, air density rapidly increases, making refraction effects much stronger along the bottom edge of the solar disk compared to the top. The difference bends or "lifts" the bottom half of the solar disk into the top half, flattening an otherwise circular Sun into an oval.

You can see the Sun several minutes before it actually rises due to strong refraction at the horizon which bends light rays upward into view.
Sciencia58 / CC BY-SA 4.0

Even before the Sun has physically risen in the morning, refraction elevates its upper edge, causing it to appear nearly 3 minutes (at mid-latitudes) beforehand. Likewise, the actual Sun sets several minutes before its refracted light does. If you were to remove Earth's atmosphere at sunset, sunlight would disappear the moment the entire solar disk sets.

So, we'll need to add another 5 to 6 minutes of daylight to the equinox due to Earth's atmosphere. Even if we were to imagine a hypothetical point at the center of the solar disk instead of the full Sun, atmospheric refraction would also lift it into view earlier and hold onto it later just like all celestial sources.

On an airless Earth, we could watch the solar corona precede the sunrise by blocking the glaring white solar disk from view. All would proceed unaffected by refraction.
Stellarium

EQUAL LIGHT ON THE EQUILUX

Are days and nights ever 12 hours apiece? Yes! Well, close. This occurs at the equilux, a delightful word that derives from the Latin equi (equal) and lux (light). While the equinox occurs across the planet at the same moment, the equilux varies according to latitude.

In the Northern Hemisphere, it occurs several days after the autumnal equinox (on September 25th or 26th at mid-northern latitudes) and several days before the vernal equinox; in the Southern Hemisphere, it's the other way around.

At the equator, day and night are never exactly equal — daylight always exceeds night by 6 to 8 minutes due to the Sun's large apparent size. At the same time, though, day and night are nearly equal every day of the year.

City Latitude Approximate date of equilux

Anchorage, Ak. 61° Sept. 25

Calgary, Alberta 51° Sept. 25

Champaign, Ill. 40° Sept. 26

New Orleans, La. 30° Sept. 27

Honolulu, Hawai'i 21° Sept. 28

San José, Costa Rica 10° Oct. 4

Bogotá, Colombia 5° Oct. 19

Quito, Ecuador 0° Never

Traveling south, equilux dates increasingly part from the equinox date.

Data from Stellarium and other sources

While the equilux concept is great in principle, a perfect balance of day and night isn't possible from many locations because daylight is decreasing at the rate of 2 to 3 minutes per day, not minute by minute. For that reason day and night lengths often differ by about a minute. For example, in Detroit the equilux occurs on September 25th, when the time between sunrise and sunset is only about 13 seconds shy of 12 hours. In Phoenix it occurs on the same date, but daylight is a little more than a minute longer than night.

Isn't splitting hairs fun?

Fall leaves frame the waning gibbous Moon in early October 2020.
Bob King

The equinox is a happy time to be a night-sky watcher. Insects retreat, and evening temperatures are cool and pleasant. To stand under a dark sky before 9 o'clock is a joy. During the summer many of us start observing at the very time we should be getting to bed. These chances occur because of Earth's tilted axis. As the Sun hastens south, the curtain of darkness drops incrementally earlier. Before you know it, the insatiable night will make sunshine a prized commodity.

Happy equinox and equilux indeed!

Bpl.org

https://www.bpl.org/blogs/post/the-origins-and-practices-of-mabon

The Origins and Practices of Mabon | Boston Public Library 

Sep 20, 2019 ... Mabon is a pagan holiday, and one of the eight Wiccan sabbats celebrated during the year. Mabon celebrates the autumnal equinox.

En.wikipedia.org

https://en.wikipedia.org/wiki/Mabon

Mabon - Wikipedia 

Mabon, the Autumnal equinox in some versions of the Pagan Wheel of the Year · Mabon ap Modron, a figure in Welsh Arthurian legend · Maponos, a pre-Christian ...

History.co.uk

https://www.history.co.uk/articles/mabon-the-pagan-festival-that-marks-the-autumn-equinox

Mabon: The pagan festival that marks the autumn equinox 

However, it is now, though a purely pagan/neo-pagan holiday, and one of the eight Wiccan sabbats celebrated during the year. Mabon occurs between the 21st and ...

Cosmopolitan.com

https://www.cosmopolitan.com/lifestyle/a37051456/how-to-celebrate-mabon

How to Celebrate Mabon 2023, Holiday Meaning & Celebrati... 

Aug 16, 2023 ... Mabon is essentially a harvest festival. Ancient Celts and pagans used this day to give thanks to nature for a good harvest and to pray to their ...

Diversity.iu.edu

https://diversity.iu.edu/cultural-involvement/holiday-religious-observances/description/autumn-equinox-mabon.html

Autumn Equinox (Mabon): Description: Religious Holidays and ... 

Autumn Equinox (Mabon) (Mah-bon or May-bon). While Mabon is not one of the four major sabbats in Wicca, it is one of the eight and is thus significant. It ...

TODAY
This year, the equinox will occur on March 19, which means the earliest first day of spring in more than 100 years.

Thursday marks the first day of spring, and the new season will be ushered in with the biannual phenomenon known as an equinox.

The spring equinox is one of two that occur each year, with the other ushering in autumn. During each of the equinoxes, there are nearly equal parts of daylight and night, and this year the spring equinox is occurring earlier than it has in more than a century, according to the Farmer's Almanac.

The last time spring arrived this early was in 1896, and for the most part, the equinox has occurred on March 20 or 21. This year, it is set to take place on Friday at 3:50 a.m. Greenwich Mean Time, according to the National Weather Service (NWS). That's equivalent to 11:50 p.m. on Thursday for New York City.

During an equinox, the Earth's axis isn't tilted toward or away from the sun, so the sun shines directly over the equator, according to the NWS. This is why day and night appear equal in time.

For the Northern Hemisphere, the equinox means earlier sunrises and later sunsets because that hemisphere tilts toward the sun. The opposite is true for the Southern Hemisphere, where the autumnal equinox is occurring, which means shorter days.

A day-old lamb explores new surroundings on the first day
 of spring, March 20, 2019, at Coombes Farm in Lancing, 
England. ANDREW HASSON/GETTY

To celebrate the biannual occurrence, people gather at Stonehenge, a prehistoric monument in England. It's unclear if the celebration will happen this year, given the coronavirus outbreak. Newsweek reached out to the English Heritage Society, which manages the monument, but did not receive a response before publication.

ICYMI

The fall equinox is here. What does that mean?

by Maddie Burakoff

The sun sets beyond the downtown skyline of Kansas City, Mo., as the autumnal equinox 

marks the first day of fall Saturday, Sept. 23, 2023

During the equinox, the Earth’s axis and its orbit line up so that both hemispheres get an equal amount of sunlight. Credit: AP Photo/Charlie Riedel, File

Fall is in the air—officially. The equinox arrives on Saturday, marking the start of the fall season for the Northern Hemisphere. But what does that actually mean? Here's what to know about how we split up the year using the Earth's orbit.

What is the equinox?

As the Earth travels around the sun, it does so at an angle.

For most of the year, the Earth's axis is tilted either toward or away from the sun. That means the sun's warmth and light fall unequally on the northern and southern halves of the planet.

During the equinox, the Earth's axis and its orbit line up so that both hemispheres get an equal amount of sunlight.

The word equinox comes from two Latin words meaning equal and night. That's because on the equinox, day and night last almost the same amount of time—though one may get a few extra minutes, depending on where you are on the planet.

The Northern Hemisphere's spring—or vernal—equinox can land between March 19 and 21, depending on the year. Its fall—or autumnal—equinox can land between Sept. 21 and 24.

What is the solstice?

The solstices mark the times during the year when the Earth is seeing its strongest tilt toward or away from the sun. This means the hemispheres are getting very different amounts of sunlight—and days and nights are at their most unequal.

During the Northern Hemisphere's summer solstice, the upper half of the earth is tilted in toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22.

Meanwhile, at the winter solstice, the Northern Hemisphere is leaning away from the sun—leading to the shortest day and longest night of the year. The winter solstice falls between December 20 and 23.

What's the difference between meteorological and astronomical seasons?

These are just two different ways to carve up the year.

Meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1.

Astronomical seasons depend on how the Earth moves around the sun.

Equinoxes, when the sun lands equally on both hemispheres, mark the start of spring and autumn. Solstices, when the Earth sees its strongest tilt toward or away from the sun, kick off summer and winter.

© 2023 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.

It's the first day of spring: Here's what that really means