Autumnal Equinox 2020: The First Day of Fall

Facts & Folklore About the Fall Equinox

September 18, 2020
Autumn in Colorado
Pixabay

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.

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Reader Comments

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THE QUESTION I ASK IS THE

THE QUESTION I ASK IS THE EQUATOR MOVING NORTH BECAUSE I WAS IN FLORIDA AND THE SUMMER HEAT WAS INTENSE AS FOR WINTERS THE LAST SNOW STORM IN PHILLY WAS 1993 WAS THE WORST I EVER SEEN IS PHILLY GOING TO HAVE A SNOWSTORM LIKE IN 1993

I can tell when autumn is

I can tell when autumn is closing in. The leaves turn a dull green/grayish. I love the Fall-my spirit is never as alive as when autumn comes. Cant wait for the big storm that blows gusty cool wind signaling the true autumn season. Fire pit and friends along with the smell of burning leaves. Awesome!

Dear Mr. Pumpkin, I also love

Dear Mr. Pumpkin,

I also love the fall. To me it is a time for renewal, and it is a time to reflect on what may lie ahead. I love the smell of fall. The leaves when they are wet, and the wood burning in the fire pit. I love the taste and the smell of apples, including hot apple cider, apple pies, and caramel apples. I love the fall county fairs, and beginning of football season. I love going to the park and tossing the football while looking at the bright orange and red color of the leaves as they fall to the ground from the trees. Mr. Pumpkin I hope you have a lovely fall and by reading your words, I know that you will appreciate every moment. Peace - "Elle"

Ny fall in New England

Ny fall in New England unofficially began last Sunday when I went apple picking and had Apple Cider Donuts! Best time of the year!

I agree with you I live in

I agree with you I live in the san francisco bay area and the summer is hot and sometimes sticky, and I know when the fall approach is time for some renewal and some relief I love the fall season

My favorite season! I too

My favorite season! I too love the smell of burning leaves and wood burning fireplaces. Here we have truly awesome sunsets in the fall. I could never understand those who say "everything dies and it gets dark so early". Love being cozy.

There is no Fall season like

There is no Fall season like Virginia beautiful colored leaves and beautiful mountain sunsets.The winters are great too snow on the mountain tops,great time for skiing and snow boarding.In the summer plenty beautiful green trees to keep you cool.The spring you smell the green grass and the leaves and the rainy month of April.Seasons in Virginia are like the four seasons you read about Wonderful!

Ms. Mitchell, I saw your

Ms. Mitchell, I saw your name. It took me back in time. I knew a woman named Zenobia (different last name of course) when I was 12. She played a pivotal role in my young life. Zenobia. It is such a beautiful, unique name. As I'm sure you are too. Be well.

IN MINNESOTA ITS LIKE FREAKIN

IN MINNESOTA ITS LIKE FREAKIN FREEZING!!!!!!!!!!!

I agree. I live in

I agree. I live in MinneSNOWta too. I don't like fall because it means winter is on its way. I can't stand winter. It's too cold and too much snow. Every year, as I get older, it gets worse. The leaves changing colors are definitely pretty and I love the smell of the crisp cooler air...just don't like what follows. Winter sucks!! Fall....has its good points and its bad.

Autuimn

I also live in Minnesota. I love autumn, the leaves, the smells, the sweaters, fireplace, campfires etc, but here autumn does not last long and winter stays for a long time. I think our short Autumn really makes us appreciate the fall weather while we have it.

October 19th and the evenings

October 19th and the evenings are cool again in Los Angeles after the latest round of hot days (hopefully the last until next year). I love that golden light from the autumn sun in the late afternoon. I wish I lived in an area with lots of deciduous trees...I'd be loving the color.

What are the different

What are the different factors that would make for an "Indian Summer"?

Hi, Brad, Good questions.

The Editors's picture

Hi, Brad, Good questions. Different folks have different interpretations. The Old Farmer's Almanac has long adhered to the saying, "If All Saints' (November 1) brings out winter, St. Martin's (November 11) brings out Indian summer." Here's our page on Indian Summer and the criteria: http://www.almanac.com/content...

What determins when the

What determins when the autumn leaves change? Temp and/or length of daylight?
Tks!
Brad

Answer: Length of daylight.

Answer: Length of daylight. ;-}

Actually, it's more an effect

Actually, it's more an effect of the temperature, as it's the freeze that kills the chlorophyll not the hours of sunshine. However when there are more hours of sun it's more likely to give the chlorophyll a chance to rebound. Not to mention shortening the time it's exposed to the colder temperature.
God bless

Here in southern Ohio, the

Here in southern Ohio, the leaves are slowly changing; others have already turned and fallen off completely! But I absolutely love fall and all that comes wit it...bonfires, Halloween, gorgeous scenery and beautiful walks through the park. Happy Fall to all! Have a great day! :)

Sunrises and sunsets are

Sunrises and sunsets are different in the fall. The air smells fresh and crisp and it's refreshing on your face. I like driving with the heat on and windows rolled down.

This is my favorite time of

This is my favorite time of year! There's nothing like the smell of pumpkin bread in the oven and a pot of hot coffee brewing. Walking outside and hearing the crunching leaves underfoot. Truly the best time of the year!

I know it's autumn when I see

I know it's autumn when I see nuts on the ground around my house. It means the squirrels are doing their winter gathering...and inadvertent scattering.

WE LOVE THE FALL! Hello,

WE LOVE THE FALL! Hello, stars in the sky!! @--)-- :O)

My Hummers are gone

My Hummers are gone And my Cosmos petals have fallen But, I know more's in store And that's why I'm not bawlin'
~Patti Poff~

From Chicago . the leaves are

From Chicago . the leaves are starting to turn, the crickets and grasshoppers are gone from the garden, the nights are cool, the days heavenly, flannel shirt weather. The squirrels are busy burying the acorns and the smell of firewood is in the air. I wait all year long for September and October and they just fly by.

Welcome Autumn! Here in

Welcome Autumn! Here in north-central California our daytime temperatures are still fairly hot (90-ish), with our nights cool 60-ish). We've had a very dry summer and need rain desperately. No real signs of autumn yet, but hopefully there will be soon.

I grew up in the midwest and

I grew up in the midwest and love fall and the leaves changing colors!! I miss the leaves changing colors, raking the up, and jumping into the big huge pile of leaves!! Here in Phoenix we have a FEW more days of 100+ days of hot weather!!! Then it just might start to cool off into the middle to high 90's!!! Wish it would cool off more!!! Really miss the days of Fall of Wisconsin!!!!

Autumn

Nothing like Wisconsin seasons :)

Love this time of year!

Love this time of year! Nature is preparing to rest. The winds are blowing crisp and there's a freshness in the air! The days have become comfortable and the chilly nights make for a restful sleep. Love cooking "comfort" foods that puts a smile my family's face.

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