A Story of Seasons

By Meinolf Wewel - Own work, CC BY 3.0, Link

This past Wednesday marked the autumnal equinox for 2021 where I'm situated.  For those reading who might not be familiar with an equinox, it's considered a day in the year when day and night are very near equal.  This usually amounts to the day when a location experiences close to an even split of 12 hours of daylight and 12 hours of night.  What makes it "autumnal" is that it happens in the season of Autumn (or Fall dependent on how you grew up learning about seasons).  Despite this day not being a great indicator of an area's local climate, per se, it is generally observed as the "first day of autumn."

I have a certain fondness for fall.  There's a warmth the word carries in contrast to the cooler temperatures that the season invites.  Or at least that's how I've typically experienced the concept.  It's the time of the year I'll start swapping out readily accessible shorts for readily accessible flannel pants.  Short sleeves for long sleeves.  Fireplaces become a actively used amenity where people have them, carrying a scent of wood through open chimneys into the air.  And just about every food and drink shop breaks out the cinnamon, a notably "warm-flavored" spice in my book.

Of course, there's no reason these sensations have to be locked to autumn.  Well, maybe you wouldn't opt for long-sleeves in summer, but fireplaces and cinnamon don't have to lose their flair in the winter, yet somehow they do.  I could approach this from a branding cynicism where local shops want to entice you with new seasonal items, and the more they change with the seasons, the more opportunities they have to present you a novel experience for the year.  There's certainly truth in that, but seasons weren't built for the human capitalist machine.  No, that machine merely adopted seasonality.  But did humans adopt them too?  Are seasons an invention or a discovery of humanity?

Let's dive in!

An Astrological Point of View

Going back to the our recent equinox is a decent place to start.  Humans have traditionally experienced seasons in the form of a measurement of sunlight divided across one rotation of the Earth.  A day, that is.  What makes this a concept we've historically deemed worthy of measuring is due to the Earth rotating on a tilted axis.  This "axial tilt" in combination with the Earth's orbit around the sun makes the amount of sun certain portions of the Earth experience different throughout the year.

By following Duoduoduo's advice, vector image: Gothika. - [1], CC BY-SA 3.0, Link

This phenomenon is most prevalent at "mid-latitude" regions on the Earth.  These are the large swathes of area between the Earth's equator and poles.  When we look at the northern and southern hemispheres of the planet and see how that axial tilt works in tandem with the Earth's orbit, we can see that when the southern hemisphere is experiencing more direct sunlight, the northern hemisphere receives less by contrast.  Essentially, whichever hemisphere more-directly facing the sun, the longer the sun can shine on it.  In retrospect, it's really less that the sun is directing more sunlight than it is the Earth is directing parts of itself more toward the sun.

At the extremes, we also have the equator and the poles.  The equator is more or less always being directed toward the sun.  We'll see in a bit that this impacts the seasons in these regions.  The poles have another interesting aspect, though.  Whether the Earth is getting sunlight depends on whether the sun is perceived over a location's horizon line.  Due to the poles' locations with relation to the sun and the Earth's tilt, they experience times where the sun doesn't "set" for days, called Polar Days, or by contrast times where the sun doesn't "rise" for days, called Polar Nights.  These phenomena really demonstrate that how we describe the sun as "rising" and "setting" is all a matter of illusion based on your present location.  We are the thing in motion, not the sun, despite our phrases anchoring to a notion that the opposite is true.  Just a fun fact about how we perceive days and direct sunlight!

Differing Seasons for Differing Reasons

So, generally speaking, humans like to associate seasons to how much direct sunlight we experience over the course of a day.  We go through these cycles, however we choose to identify them, in the same way with every revolution of the Earth around the sun.  This happily coincides with the 12-month calendar, also a method of tracking the Earth's path around the sun.  This overlap gave rise to 2 major ways to track the seasons in the modern world: the 4-season and 6-season year.

The 4-season year is the model I'm used to experiencing in the United States.  This is composed of Spring, Summer, Autumn, and Winter.  We track these by way of equinoxes (times of roughly equal daylight and nighttime) and solstices (times of longest daylight/shortest nighttime and vice versa).  In southern Asia, we have the 6-season calendar which adds a monsoon season and, depending on location, observes early or late variations of spring, autumn, or winter.  To fit with the 12-month calendar, the 4-season variation is split into even 3-month chunks while the 6-season variation is split into event 2-month chunks.

This even split of seasons over the 12-month calendar year, though, is pretty arbitrary.  What exactly is the point of a larger span of time that fits into the 12-month year?  We already have a means of tracking reasonably long spans of days in the form of months.  The acknowledgment of seasons seems a bit extra, if I'm being honest.

Until we back up a bit more.  While our modern day seasons are generally mapped to the 12-month calendar, the seasons have historically tracked something else: ecological changes in the environments we live in.  Spring doesn't "start" on the vernal equinox.  Spring is a rough concept that maps to the budding of plants local to where you live.  Summer doesn't "end" on the autumnal equinox.  It's a transition from fully-leafed trees to when the leaves change color and fall to the ground.  We could still very well be in Summer when the first leaf falls, and, like this year, a majority of the trees around me haven't even begun to change color last week.  The Earth doesn't know Wednesday was the autumnal equinox.  It's just a day on a calendar.

Instead of mapping these astrological events to a calendar, our ancestors would mark seasons with ecological change.  Currently, in mid-latitude regions, we experience 6 named ecological seasons: Prevernal (early spring), Vernal (spring), Estival (high summer), Serotinal (late summer), Autumnal (autumn), and Hibernal (winter).  These 6 seasons aren't tied to any particular date or astrological event, but instead by changes in a local environment.  These can be things like budding of flowers, leafing of trees, migrating birds, and the barrenness of the land.

Seasons have also been used in a cultural sense.  If an indigenous tribe's livelihood is dependent on water, it was not uncommon to have a season to mark when the waters begin to freeze before winter and break before spring.  Humans have also named seasons not only for the environment they find themselves in, but also for how they map their social livelihood to that of the world around them.  It's through these human-nature parallels that we get names such as "season of the young" and "season of birth" from some cultures around the world.

Then there are areas like the tropics, regions positioned about the Earth's equator which, as we mentioned briefly, don't experience much difference in the amount of sunlight they receive day-to-day over the course of the year.  These more constant sunlight conditions don't affect the local flora and fauna in the same way that the mid-latitude sunlight changes do.  These regions do still track seasons, just more in a wet and dry seasons dichotomy.  Instead of sunlight being a driving factor in annual ecological change, the ocean currents and wind system play larger roles.  We still hear the terms "wet" and "dry" seasons for these areas since these ecological seasons are still extremely helpful for these regions and the calendar seasons don't map well to tropical regions.

A Story of Seasons

You might notice that in both the calendar and ecological cases, seasons aren't the most helpful as denominations of time.  In the case of the calendar seasons mapped to astrological events, they certainly fit snugly into regular calendar intervals, but humans don't track time in seasons as much as we do days and months.  In the ecological case, these seasons deliberately divorce themselves from depending on regular time intervals because the world is complicated and full of nuance.  So if the seasons aren't particularly helpful from a time-keeping perspective, why do we track them.

If I were to wager my best guess: affecting human behavior.

Think about it this way.  The Earth works in a highly cyclical fashion.  While the exact days of these repeating events are never the same from cycle-to-cycle, we can be reasonably sure they will keep happening.  The rains will fall giving rise to the budding plant that grows to maturity making its seeds to be dispersed and find a new home before the winter locks them into the ground to bud when the next rain arrives.  With each of those portions of the cycle, there comes varying degrees of drastic shifts in the environment around us, be it from which plants are available, which animals are still in the area, or just how hot or cold or dry or wet it is.

By giving these changes in our surroundings names, we turn these cycles into chapters of a story.  A story where we can always see when the page is about to be flipped.  A story easy to grasp from the youngest to the oldest of humans.  And along with these stories are the habits we practice at the same time.  From comfort things like making sure your flannel pants are more easily accessible when it's about to start getting colder outside to survival things like maintaining your window shutters as monsoon season approaches.  I don't think we, as humanity, ever intended to map seasons to a calendar, that's a happy accident.  No, I think we invented seasons to tell stories of how to survive in a cyclical world.  Stories told in both practice and the oral tradition to ensure we never forgot what was around the corner.  Stories with the intent to plan so we can use what's certain in the world to make the unpredictable easier to navigate.

In the end, seasons are really a storytelling mechanism, a piece of our tradition that helped us survive to the days we experience today.  They're a tool to make our cyclical behavioral changes easy to remember.  Heck, sometimes we even celebrate them to anchor our collective selves to behaviors that give us the greatest odds of survival.  And, personally, it gives me a warm fuzzy that stories helped us adjust to survive amid an ever-changing environment.  Or maybe that's just the autumnal flannel pants talking :)

~ And, as always, don't forget to keep wondering ~

Sources:
General Terms Reference
https://en.wikipedia.org/wiki/Season​