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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Autumn light - Sunlight

Yes, I too have noticed a difference in light. I believe it is due to a shift, as the earth moves farther away from the sun.

It does have a very nice glow about it too!
Enjoy your fall season:)

Autumn Light- Sunlight

You are so right Valerie! I noticed the Glow myself. I just love Fall it's my favorite season. Blessings!

Hello Fall

As an early riser who enjoys the dawning of a new day, I miss the morning daylight as it arrives later in the morning. When I leave the house that beautiful ball of light and fire is in a different location. I've noticed that it isn't as hot. The temperature also has changed in the morning and at night. Good night summer, and hello Fall!

I could smell the difference

I could smell the difference in the air in the middle of July. And the color and look of the sky is different. The energy around me me is different as well. All of this in the middle of July.

July

I agree with you about beginning to see the Autumnal changes in late July, even here in Texas. I love the changing of the seasons! I believe in some cultures, they consider August 1 to be the beginning of autumn. Have a wonderful season!

Changing from Summer to Fall

I felt autumn a couple of weeks ago. It starts in July. The first inkling is the light starts to change. Predawn light starts a little later everyday. Dusk starts a little earlier everyday. I notice the sun is now in a different position in the morning and at dusk. Shadows are just a bit more pronounced.

FALL

Yes I felt it yesterday. was laying down looked out side and something about the lighting made me feel that fall was not far. Cant wait my favorite season.

FALL

Yes I felt it yesterday. was laying down looked out side and something about the lighting made me feel that fall was not far. Cant wait my favorite season.

September

Fall lasts 4 months, and Christmas lasts 3 weeks. I decorate for fall. The nativity is enough for Christmas.
"September" by Helen Hunt Jackson
1 The golden-rod is yellow;
2 The corn is turning brown;
3 The trees in apple orchards
4 With fruit are bending down.

5 The gentian's bluest fringes
6 Are curling in the sun;
7 In dusty pods the milkweed
8 Its hidden silk has spun.

9 The sedges flaunt their harvest,
10 In every meadow nook;
11 And asters by the brook-side
12 Make asters in the brook,

13 From dewy lanes at morning
14 The grapes' sweet odors rise;
15 At noon the roads all flutter
16 With yellow butterflies.

17 By all these lovely tokens
18 September days are here,
19 With summer's best of weather,
20 And autumn's best of cheer.

21 But none of all this beauty
22 Which floods the earth and air
23 Is unto me the secret
24 Which makes September fair.

25 'T is a thing which I remember;
26 To name it thrills me yet:
27 One day of one September
28 I never can forget.

The First day of Fall

This beautiful day will always be forever in my heart as the day I said "I do".

Outside with the changing leaves around us, my love and I became husband and wife.

We walked on a pathway of pumpkins and mums, to a floating stage of sunflowers.

Five years later and many memories made, we moved into our new home on the 22nd of September.

Fall

My Grandmother always said that it was never officially Fall until the Spider Lillies bloomed. I look for mine every year (they bloomed last week here). I think of her when I see them.

My animals tell me what kind of winter it's gonna be

When my cats and horses start getting thick coats early, I know the winter is gonna be COLD and hard. If they're slick up until Thanksgiving, I know a winter is gonna be mild.

Stink bugs! All over the

Stink bugs! All over the house. That's how I know fall is here.

How Do I Know It's Fall?

I know it's fall when the black walnut tree drops its green balls! We collect them and give them to our squirrels and chipmunks and they have a ball biting into them, running with them, storing them. The red squirrel is the quickest to grab them! : )

equal day and night

Wouldn't the day be slightly longer than the night, because of the diameter of the Sun? If it was a point source it would be exact, but it is not a point source.

day length

The Editors's picture

Daylight is longer than nighttime at the actual equinox, in part because the Sun is a disk, not a dot, and of the definition of sunrise and sunset, and therefore, length of day. Daytime is defined as beginning when the upper edge of the Sun reaches the horizon (which happens a bit before the center rises), and it doesn’t end until the entire Sun has set. So, that adds a little time (a few minutes) to daytime. If the Sun were a point, then we wouldn’t have those extra minutes. Also, because of our atmosphere, which bends light, the Sun appears a bit higher than it actually is. Therefore, it makes sunrise occur a little earlier and sunset a little later, which also adds a bit of time. How much time depends on latitude. It the Sun were a point, and we didn’t have atmosphere, then daytime and nighttime at the equinoxes would be 12 hours each.

For any day, you can find the rise and set times of the Sun, Moon, and planets, as well as day length, for your area, at this page:
http://www.almanac.com/astronomy/rise/

Hope this helps!

Autumn is coming

The darker early mornings that were once day. Especially around 6:30-7A.M.! Midday and early evening times seem more of a fall look in the sky as well. Some days, I smell the Autumn in the air around this time frame and it has that Autumn look and feel. Big giveaway is when the Georgia National Fair arrives in Perry, GA!! :0) Hope these helped or maybe someone else can relate to these signs I see and feel. Don't quote me on these! Just going by my OWN opinion!

How we know Fall is coming!

We live on a National Bicentennial Farm in the Blue Ridge Mountains of Virginia. We're fairly remote where we are in Grayson County, and our farm is surrounded on all sides by mountains. Because of this, we are very attuned to nature, and wild life. The mountains make a giant calendar all around us, where we can pinpoint any time of year by where the sun sets and rises, and at night mark the change in the position of the Milky Way. Also because of the mountains around us, there's an abundance of wildlife, and we can mark the coming of Fall by their changes as well. The crickets drown out the dawn chorus of the birds as Summer winds down, and as Fall approaches, they go all day and night as opposed to just at night. The second most prominent wildlife change is that the Screech Owls become far more vocal at night, when I hear those, I know Fall is on it's way! The cows become fussier because it's usually dry here at the end of Summer, and there's less choice grass for them to eat, meaning they have to be moved more often. Finally, the mountains themselves begin to change. Long before the leaves themselves turn, the mountains go from lush uniform green, to a very faint, but discernible undertone of different colors barely visible under the green of the leaves. Fall and Winter are my favorite times of year here, and I look for these signs every year to let me know that my first favorite season is on its way! I'm listening to those crickets right now!!

Beautiful description

Love your essay! Your description of the mountains being your calendar is very charming! Enjoy the upcoming beauty!

Your essay

The most beautiful feeling I've ever had just became words from your fingertips. Thank you.

Beautiful

Please keep writing about all the seasons on your farm! It sounds like the perfect place to be to witness their changes, and you have a wonderful way of describing them. Thank you.

How We Know Fall is Coming by M.S. Greene

You my friend, have a Greene thumb for writing.

Wonderful!

Sounds like you are living in Eden! Your descriptions are so evocative, I could just about smell the air where you are. You didn't need to attach a picture as you painted such perfect pictures in words, but I wish you had! Please share more! I'd like to think you feel pretty blessed to be on your place. Lovely, just lovely. Thank you.

when does winter start

when does winter 2016 start in South Florida?

When does winter start?

The Editors's picture

In the Northern Hemisphere, winter begins on December 21, 5:44 A.M. EDT. See our page about First Day of Winter here: http://www.almanac.com/content/first-day-winter-winter-solstice   Note that how you define the first day of winter depends on whether you are referring to the astronomical or meteorological winter. Most calendars (including ours) refer to the astronomical seasons which are a result of the Earth’s axis and orbit around the sun.

Winter

That's a good one Yarissa! Winter in South Florida. They have summer and a really long spring.

transplant trees/knock out roses

When can you trans-plant knock-out roses, boxwood trees and crept myrtle trees?
please advise,
monika

spring

My grandfather always said in the south east area of the united states "when pecan trees bud there will be no more frost !"

Thumping on the Roof Top

Thumping on the Roof Top

Though there be no sign in the leaves, Fall lets us know it's coming around- -the-been by the syncopation of acorns falling all around the yard and imitating hail on our roof. We have two large White Oaks, one in the front and the other in the back yard that start giving away a bonanza of fruit in the first week of September. The critters, squirrels and chipmunks respond like it was an invitation to a ball. They're actively eating, burying, hoarding, and chasing each other around as some kind of instinctual dance rite sponsored by Mother Nature herself. So in the Capitol Region of NY, before all the other undeniable aspects of Fall sets in, the oak trees and their acorns are first to announce the annual change of the season.

I assume twilight lasts about

I assume twilight lasts about the same for both the spring and fall equinoxes, and that summer twilight would be shorter than winter because in the summer the sun sets more perpendicular to the horizon than the winter.

Good theory??

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