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.

SUPER DISCOUNT!

Celebrate Almanac Tradition and Save 57% with a Charter Membership in The Old Farmer’s Almanac Best Value Club

Best Value Club

You are invited to join The Old Farmer’s Almanac Best Value Club at a Special Savings!

An incredible value—57% off for you!
For traditional Almanac fans:
Just $29.97! You save 57%!

Get the best value for your Almanac dollar with these essentials. Claim you Old Farmer’s Almanac Best Value Club Charter Membership today!

YES, sign me up now!

Reader Comments

Leave a Comment

Here where I live in MA the

Here where I live in MA the trees are still green and I still hear the peepers at night as well as cicada's during the day. We have has cooler nights (upper 50"s) and the days haven't been out of the 70's all week. My window looks out over the woods and I am looking forward to seeing the color change in the leaves.

in neo the fall transition

in neo the fall transition seems to be a month early.but I do enjoy it

Fall is coming

Fall is coming

Here where I live in MA I

Here where I live in MA I still am hearing the peepers and cicada's. The leaves are still green. The only thing that is telling me the season is changing is it's been in the 50's at night which is nice to sleep in. The days haven't been out of the 70's for the past week.

Here in Southern Ontario, the

Here in Southern Ontario, the days are getting slightly cooler, and the nights are definitely lots cooler!

I love everything about OFA

I love everything about OFA and Autumn! I just wish we could have 4 months of Autumn temps and colors, unfortunately we get to look forward to temps over 100+ for another month here Central AZ:(

Will Autumn ever get here?!

Here in the South (Memphis, Tennessee) Summer begins at Easter and lasts until Halloween. This year, we went from April to August in about two or two and a half weeks' time. It was 75, and THEN IT WAS 95.... The crape myrtles that don't normally bloom until late July bloomed in early May. I cannot wait until Thanksgiving.... I am already so tired of heat indexes and Code Orange ozone alerts and excessive heat warnings. :(

in Missouri, nights are

in Missouri, nights are becoming a little cooler, and heat-stressed trees are starting to turn.

Now this is some very

Now this is some very interesting information. I really learned a lot by reading these questions and answers. Thank you so much for publishing this educational information. There is much here to absorb.

I absolutely love it when

I absolutely love it when fall comes. It is my favorite time of year. I cannot wait to break out my sweaters and hoodies. Thank you for this report and I can't wait to read more from you.

 

 

If we see the legalism of an casino online anytime soon I will wager at the slot machines but only the ones that are honest.

I agree Maryjane ,it`s my

I agree Maryjane ,it`s my favorite time of yr too,I love the smell in the air ,the beauty of the changing leaves ,and the cool nights........my cats love it too!!

Even though I am in Florida,

Even though I am in Florida, I notice the mornings being just a tad cooler. By cooler I mean not so humid! But, it is nice. In a few weeks when the evening weather cools, too, my cats also love it. They get almost as frisky as their mama!

I see flocks of migrating

I see flocks of migrating birds wheeling overhead and sometimes dropping down onto the pond to rest for a bit; the male hummers have left; and the air feels crisper somehow.

even in texas at some point

even in texas at some point you can catch a scent of autumn on the breeze. of course the heat here does not end until way later, being from kansas i have a keen sense of the air. autumn is the best time of year!

I wish that would happen in

I wish that would happen in Houston nowadays ... we are facing another week of 100+ F.

Fall

Me, too. And summer has only just begun.... I can't wait until Fall.

I wish that would happen in

I wish that would happen in Houston nowadays ... we are facing another week of 100+ F.

We live in Houston,

We live in Houston, too....but i see a cool front on the horizon Monday the 26th, let's hope and pray! take care neighbor!

Yeah I see a cool front also

Yeah I see a cool front also it will only be in the upper 90"s instead of 100 what a cool down!

It is 76 degrees right now in

It is 76 degrees right now in Fort Worth. Thank goodness summer is over for us. High of 83 today.

Wow! Y'all have it HOT! Here,

Wow! Y'all have it HOT! Here, near the heart of Indiana, we're bracing for a 40 degree night! Signs of fall here are the sales on furnace filters and the RISE of heating oil prices! $4.00 a gallon this year, needing 250 gallons TWICE to get us through the winter, into spring! But, we're still going to enjoy our fall colors and all the increased critter activity!

Have you tried to search

Have you tried to search information on google?

I'm not in Houston, although

I'm not in Houston, although I used to be stationed in Texas. I'm in NH now. For us the 26th is this Friday, the day after my birthday. Either way I hope your cold front is cold and not a tease.

Hot out in Los Angeles

Hot out in Los Angeles too,downtown on Saturday got to 103°!!

You're obviously not a

You're obviously not a teacher.
I Love Summer!

And you're obviously not from

And you're obviously not from Texas!

I bet a lot of Texans count the seconds on their watches until Autumn. Talk about extreme summers.

The "temperatures" in the southwest are higher. The "humidity" in Florida is higher. But Texas has just enough of them both to make it unbearable for most people.

100+ with high humidity is enough to make many people have a heat stroke. I can tolerate 90 degrees of Florida heat and 110 of Vegas heat but when you mix the two... it's just deadly.

The first signs of fall I see

The first signs of fall I see is when I smell a lot more wood stoves burning. My dad and I love that smell! Also, I see leaves changing colors and the nights creeping up on me earlier and earlier each day.

I AWOKE THIS MORNING IN

I AWOKE THIS MORNING IN EASTERN PENNSYLVANIA, LOOKED OUT THE WINDOW, AND THOUGHT IT WAS CLOUDY AND OVERCAST. A FEW MINUTES LATER I SAW THE RISING SUN CASTING LONG SHADOWS AND BLAZING STREAKS ACROSS MY BACKYARD (THE NORTH FORTY)...IT WASN'T CLOUDY AFTER ALL, IT JUST WASN'T DAYBREAK YET!!!

Pages