Autumnal Equinox 2020: The First Day of Fall

Facts & Folklore About the Fall Equinox

September 18, 2020
Autumn in Colorado

In 2020, the autumnal equinox—also called the September equinox or fall equinox—arrives on Tuesday, September 22. Fall begins in the Northern Hemisphere and spring begins in the Southern Hemisphere. Read about the signs of fall and the ways we mark the approaching equinox. 

Autumn has caught us in our summer wear.
–Philip Larkin, British poet (192286)

When Is the Autumnal Equinox?

The fall equinox arrives on Tuesday, September 22, 2020, at 9:31 A.M. EDT. The equinox occurs at the same moment worldwide.

Autumnal Equinox Dates and Times

Year Autumnal Equinox (Northern Hemisphere)
2020 Tuesday, September 22
2021 Wednesday, September 22
2022 Thursday, September 22
2023 Friday, September 22

What Is the Autumnal Equinox?

Autumn days come quickly, like the running of a hound on the moor.
Irish proverb

The autumnal equinox—also called the September or fall equinox—is the astronomical start of the fall season in the Northern Hemisphere and of the spring season in the Southern Hemisphere.

What Is an Equinox?

The word “equinox” comes from Latin aequus, meaning “equal,” and nox, “night.” On the equinox, day and night are roughly equal in length. (See more about this below.)

During the equinox, the Sun crosses what we call the “celestial equator”—an imaginary extension of Earth’s equator line into space. The equinox occurs precisely when the Sun’s center passes through this line. When the Sun crosses the equator from north to south, this marks the autumnal equinox; when it crosses from south to north, this marks the vernal equinox.

After the autumnal equinox, the Sun begins to rise later and nightfall comes sooner. This ends with the December solstice, when days start to grow longer and nights shorter.

Fall bridge

Fall Weather

It is the summer’s great last heat,
It is the fall’s first chill: They meet.

–Sarah Morgan Bryan Piatt

Another definition of fall is “nights of below-freezing temperatures combined with days of temperatures below 70 degrees Fahrenheit (21°C)”. From here on out, the temperatures begin to drop.

Will fall bring crisp, cool weather—or, unseasonably warm weather? It depends on where you live! See our 2020 Fall Weather Forecast.

Find 12 months of long-range weather predictions in the new Old Farmer’s Almanac!

Fall Foliage

Note that fall foliage isn’t due to current weather conditions. This is a common misconception. Leaves change color because of the amount of daylight and photosynthesis. Learn more about autumn leaves.

Japanese maple leaf in fall

Fall Equinox FAQs

Q: Are Day and Night Perfectly Equal on the Equinox?

A:  Some say that during an equinox, day and night is equal. Well, not exactly. It depends on where you live.

On the equinox, the center of the Sun is indeed above the horizon for 12 hours. However, “sunrise” is said to begin when the upper edge of the Sun’s disk becomes visible above the horizon (which happens a bit before the center rises) and ends when the entire Sun has set. In this case, daylight is still a bit longer than nighttime. 

Not only that, but the Sun is actually visible when it is below the horizon, as Earth’s atmosphere refracts the Sun’s rays and bends them in an arc over the horizon. Yes, you can see the Sun before the edge actually reaches the horizon! This causes daylight to be longer than 12 hours as well.

However, they are very close to equal (the total lengths may differ by only a few minutes). 

Did you know our rise/set tool now provides day length? In Dublin, New Hampshire, USA—home of The Old Farmer’s Almanac—our day length on the equinox is 12:08 hours.

See our Sunrise/set calculator for day length in YOUR area.

Q: Is the Autumnal Equinox Really the First Day of Fall?

A: Based on the astronomical definition of seasons, yes, the autumnal equinox does mark the first day of fall (in the Northern Hemisphere). However, according to the meteorological definition of seasons, which is based on temperature cycles and the Gregorian calendar, the first day of fall is September 1.

Q: Can You Balance An Egg On the Equinox?

A: There’s an old-wife’s tale that you can stand an egg on its end of the equinox. Well, yes, it’s true (and fun to try). But it’s not only on the equinox. See more about equinox facts from Almanac astronomer, Bob Berman.

autumn woods

Signs of Fall

What are your local signs of fall? In many regions of the Northern Hemisphere, the landscape silently explodes with vibrant colors of red, yellow, and orange. The leaves begin to drop off the trees, providing endless hours of jumping into leaf piles for kids and raking them back up for parents!

Trees snapping and cracking in the autumn indicate dry weather.

Fall also brings some wonderful holidays, including Halloween and Thanksgiving, which carry us through the season until temperatures begin to drop, nights begin to get longer, and all the woodland critters start storing up for the long haul of winter

And don’t forget about the end of Daylight Saving Time, when we “fall” back, setting our clocks back one hour and regaining an hour of precious sleep!

Plants and trees are slowing down, as sunlight decreases, to get ready for the colder season ahead. In the garden, asters and chrysanthemums bloom beautifully as orange pumpkins and corn mazes abound.

Football season is warming up and so is sweater weather.

Also notice the arc of the Sun across the sky each day as it starts shifting south. Birds and butterflies migrate along with the path of our Sun!

Of course, you can you can easily notice the later dawns and earlier sunsets. See our sunrise/set tool for your area!

Purple Aster
Aster flowers

Ancient Autumn Traditions 

The fall equinox has been a day of celebration for cultures since ancient days. People tracked the transitions of the Earth’s journeys around the Sun.

  • At Machu Picchu in Peru, an ancient stone monument called Intihuatana—which means “Hitching Post of the Sun”—serves as a solar clock to mark the dates of the equinoxes and solstices.  
  • In Mexico, the Mayans built a giant pyramid called Chichen Itza. On the equinoxes, it looks as if a snake made of light slithers down the pyramid’s steps.
  • In England, Stonehenge was also built with the equinoxes and solstices in mind.

See Five Ancient Sites Aligned With the Equinoxes and Solstices.

Enjoy Autumn!

Wishing a colorful, cool, cozy autumn to all our Almanac readers. Tell us your favorite things about the fall season below!

To learn more about all four seasons and see when they begin, see First Day of Seasons.


Reader Comments

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I live in arizona as well.

I live in arizona as well. And let's face it there's no such thing as autumn or spring here. It's either hot, cold, or we are having crazy amounts of rain and dust storms with the occasional tornado that happens like never. And it may not get as cold as some places like New York but it gets pretty cold here. People just assume that because it's a desert it's always hot, but that would be false. In some places it can get to 0° or lower, but mostly at night. The lowest I've seen it get here in the valley is about 20° but I think the record low here in Phoenix is 16°. And it can get as hot as 122° in Phoenix as well. And the record high for Arizona is 128° I believe. But like I said there really are only 3 seasons here winter summer and monsoon season.

Alexandra, My sentiments

My sentiments exactly! Love autumn but dread what follows. As I was taking my brisk walk this a.m. I found myself having mixed emotions about the scenery unfolding before me. On the one hand, I found the colorful foliage quite beautiful and uplifting, on the other, sad because I know what's coming after this season. Then I reminded myself; "Stay in the moment". I do not want to miss out on my enjoyment of this perfectly gorgeous change occurring because I am anticipating another dreadful winter. I felt better.

A friend of mine does a

A friend of mine does a seasonal autumn spread on her website. Nice fall pictures:

yes its called heaven !!!

yes its called heaven !!!

That was my answer, also!

That was my answer, also! Heaven...

Yeah i think so. Its our

Yeah i think so. Its our country, Maldives.The sunny side of life.

Suriname a nice country in

Suriname a nice country in South America.

I'm from Upstate NY as well

I'm from Upstate NY as well and I completely agree with you. Autumn is pretty but only for a short time. Summers here are not long enough and spring really begins a month late. Winters here are long, dark, cold, and never seem to end. I hope someday that I am in the position to move someplace where summers are hot and winter is scarce.

North Central AZ! I am

North Central AZ! I am originally from Cooperstown, NY. Hated the cold. Went Vegas. Hated heat. Now in Cottonwood AZ. A little heat but short and not that bad. Cold is maybe an hour or two of freezing and then warm days. Perfect climate, lots of farming, green, trees and heaven. No earthquakes, tornadoes, hurricanes but a minor flood once in a while in the summer monsoon.
Fall here is gorgeous. High 80s day high 50s night. See the stars and no pollution to clog the lungs.

I think autumn is awesome in

I think autumn is awesome in Texas, during summer it will NEVER go under 73 degrees but during fall its only 60-85 degrees. Also my b-day is in fall. I also kinda like the feel of shorter days so its darker when i sleep and my eyes dont burn of sunlight in the morning.

I love early spring, when the

I love early spring, when the leaves are that bright, bright green and I actually feel growing sadness as the summer goes by and they turn that dull, grayish green. I know that means winter is coming. See what I did there? I jumped right over Autumn! I do love the colors and smells of Autumn, but it's way too short. One good downpour and the color is gone, leaving bare dead-looking branches and chill. I guess it's best to make the best of what we are given and try to find joy in each season in turn. That being said, ever since I was a child ( too many years ago to mention) I have cried at the first snowfall. I can't help it. Perhaps I am grieving the passing of another bright, sunny time. I live in NY state, where winter seems endless.

I truly enjoyed reading your

I truly enjoyed reading your comment. I use to live in GERMANY I loved Spring festivals, and looked forward to the Oktoberfest. Old man winter brings snows there it's cold, I love it when season's change, I like the SMELL, it's a refreshing reminder – Time Waits For No One and how quickly it passes by, seasons come and The seasons go We get a little sunshine, rain or snow Just the way that it was planned and fond memories of friends, families.

Autumn wakes me up, my Spirit

Autumn wakes me up, my Spirit is at its best and I feel renewed. The Season starts with Apple picking and warm Apple Cider with Brandy in the evening. The leaves are colourful, the air feels fresher, the smell of fire wood burning in the neighbourhood. Mmm, no better time of year.

You described it so

You described it so beautifully!

Spring is definitely my

Spring is definitely my preference, when everything is coming to life...
Fall marks coming to fruition, and imminent death looms large.
I'm at time in my life, when Winter's are too hard, and Summer's too hot.
Moderation I guess. :)

Whoever invented daylight

Whoever invented daylight savings time should be banished to Alaska. I like 'cozy', I like the seasons, but those long nights can depress me a little, and I think that's a physical thing having to do possibly with light and vitamin D. I've also heard of people getting summer depression, I suppose due to overheating, which some people handle better than others, as with the cold. Actually I'd like to learn more about all this....

I agree. I truly dislike

I agree. I truly dislike Daylight Savings Time. The summers are hot enough in Florida and since I was born in Miami, even when stationed elsewhere, HOME was always FL, so I will never leave, but the summers are long and hot enough without DST. I welcome fall and can feel the change in air even if the heat does not subside much, but I had a full heatstroke in 1995 stationed at an AFB where the temp was still 107 after dark. It cause a hemorrhage in my brainstem and even after 16 months of rehab I still can't take the heat and I'm sure there are many other people who's bodies don't assimilate heat very well either.

I must say I agree as well. I

I must say I agree as well. I think it is healthier for us to start when the sun comes up and stop when the sun goes down. No need to keep DST anymore. Even here in the North the days are too hot.

I think all states should

I think all states should abolish DST. It
worked for Arizona!!

Interesting. I hate dst and

Interesting. I hate dst and I fear the summer. I live in the southwest and some people can handle it, but most are confined to living indoors with AC. This summer many nights were warm and one night at middnight it was 85 degrees. Never cooled down for weeks. It's hell.

I live in Arizona we do NOT

I live in Arizona we do NOT participate in Daylight Savings Time. As I travel to see friends in Nevada I have to adjust time 1 hour when I arrive. Makes me wonder what's the significance of the concept and the purpose of it, I'm told by elders HITLER used it to get more work out of people in general.

Really? There's no DST in

Really? There's no DST in Arizona? Interesting... I thought EVERYONE adjusts their time twice a year. Well, you learn something new everyday! I'm in NY state and we do the DST. I prefer the autumn one where we GAIN an extra hour of sleep! But I suppose it IS unnatural; we should accept the natural times and cycles of the planet the way they are naturally.

It was Ben Franklin.

It was Ben Franklin.

I love and enjoy each season

I love and enjoy each season in its time. Spring and fall are the nicest for they usually avoid the extremities of temperature. However, note the word, "usually" for there are occasional exceptions to this rule. At my age and in my health, I have learned to submit to the statement of the Apostle Paul, "I have learned in whatsoever state I am in, therewith to be content," just to be with my family and good friends, and to know the presence of the Good Lord, makes each season a blessing to enjoy.

Sorry, I'm not a fan of fall,

Sorry, I'm not a fan of fall, because winter comes right after. If I had my way, I'd go to sleep after Thanksgiving dinner, and not wake up until St. Patrick's Day. Bears have the right idea...hibernation!

I don't like SPRING because

I don't like SPRING because right after comes summer which means fall is next and then the WINTER! Oh woe is me, I'm not happy with what I have been given!!!



I love the comment, "the

I love the comment, "the leaves are changing or turning", actually the color that remains after the trees have stopped making chlorophyl(sp) is the true color of the trees leaves.

That's certainly true for the

The Editors's picture

That's certainly true for the carotenoid pigments. In autumn, as sunlight decreases and days get shorter, leaves make less and less sugar. Eventually, the chlorophyll pigments (which give leaves their green color) decrease and the green color in the leaves begins to fade. Eventually, photosynthesis finally stops, and the veins at the bases of the leaf stems sometimes close, trapping sugars.

As the chlorophyll fades, any yellow, orange, or gold carotenoid pigments that are present in the leaf are revealed.

If there are lots of sugars trapped in the leaf, and there is plenty of sunlight, anthocyanins, (red, blue, or purple pigments) may be produced as the leaf begins to die. These can combine with carotenoids to produce brilliant orange and red leaves. (Some plants have anthocyanins in their leaves throughout the growing season, such as many purple-leaved plants. In these cases, the leaves contain a higher concentration of anthocyanins than chlorophyll pigments.)

I didn't know that. Sugar!

I didn't know that. Sugar! Thanks for for sharing your knowledge.