Some Things Don’t Make Sense, but Are Almost Impossible to Change… Our 12-Month Calendar

The trouble with mankind is not that we cannot invent a better way of doing things. It is that once we have invented a sufficiently complicated way of doing something, we build an entire civilization around it—and then declare that changing it would be impractical. — YNOT!

There are certain things in human civilization that make absolutely no sense, yet we continue doing them because our ancestors did them, their ancestors did them, and somewhere along the way we confused tradition with intelligence.

Consider the calendar.

We live in an age when artificial intelligence can write computer programs, satellites can navigate us to within a few feet of our destination, and scientists can calculate the movements of planets centuries into the future.

Yet we still organize our lives around a calendar that cannot decide how many days belong in a month.

Some months have 30 days. Others have 31. February, apparently unwilling to cooperate with the rest of the year, has 28 days—except when it has 29.

We teach children a little poem to remember which months have which number of days.

Think about that.

We have built a civilization capable of exploring Mars, but we still need a nursery rhyme to remember how long November lasts.

And perhaps the most interesting thing about this ridiculous arrangement is that better alternatives have existed for more than a century.

We simply refuse to adopt them.

Not necessarily because they are worse.

But because changing something familiar may be the one challenge humanity finds more intimidating than inventing something new.

The Romans Left Us a Calendar—and Apparently Nobody Kept the Receipt

To understand our present confusion, we must visit ancient Rome, that marvelous civilization responsible for roads, aqueducts, representative institutions, and a considerable number of problems that survived the empire itself.

Early Roman calendar traditions described a year of ten months beginning in March. Later reforms established twelve months, although historians caution that some details of these early accounts are uncertain.

This explains one of the more entertaining absurdities we inherited.

September comes from the Latin word for seven, yet it is our ninth month.

October refers to eight, but it is our tenth.

November refers to nine, yet occupies the eleventh position.

And December, whose name comes from ten, sits proudly at number twelve.

Imagine buying a house where the third floor is called the first floor, the fourth is called the second, and the elevator manufacturer assures you this arrangement is perfectly normal because the Romans approved it.

That, essentially, is our calendar.

Then came Julius Caesar.

By 46 BC, the Roman calendar had drifted so far out of alignment with the seasons that drastic correction was necessary. Caesar’s reforms produced an extraordinary transitional year lasting 445 days.

Think about that for a moment.

A year with 445 days.

If that happened today, Congress would probably celebrate the opportunity to collect another eighty days of taxes.

The Julian calendar subsequently standardized a 365-day year with an additional day every fourth year. Eventually, however, even this arrangement proved insufficiently accurate.

In 1582, Pope Gregory XIII introduced another reform. Ten calendar dates disappeared in the countries that immediately adopted it: October 4 was followed by October 15.

Britain and its colonies waited until 1752 before making their own change, dropping eleven dates.

Imagine going to bed on September 2 and waking up on September 14.

Today, people would immediately blame the government, social media would declare a conspiracy, and someone would demand compensation for eleven missing days of their life.

Yet the reform worked.

The Gregorian calendar remains remarkably accurate at keeping the calendar year aligned with the seasons.

Its problem is not that it fails astronomically.

Its problem is that it remains unnecessarily awkward for organizing ordinary human affairs. And that distinction matters.

Thirteen Months, Twenty-Eight Days, and a Little Common Sense

Now consider an alternative.

Instead of twelve months of varying lengths, suppose we organized the year into thirteen months of exactly twenty-eight days each.

Every month would contain precisely four weeks.

Every month would begin on the same weekday.

Every month would end on the same weekday.

The first day of the month would always fall on the same day of the week. So would the fifteenth, the twenty-first, and the twenty-eighth.

There would be no need to remember whether February had 28 or 29 days.

No more wondering whether the 15th lands on Tuesday or Friday.

No more businesses comparing a 28-day February against a 31-day March and pretending the two periods are equivalent.

Just thirteen identical months. The arithmetic is beautifully simple.  13 × 28 = 364 days.

Of course, the Earth takes approximately 365.2422 days to complete the seasonal year.

That leaves one additional day in an ordinary year and two in a leap year.

Calendar reformers proposed assigning these extra days a special status outside the regular sequence of months and weekdays.

A year-end holiday could be called Year Day. An additional Leap Day would appear in leap years.

Suddenly, the calendar becomes predictable.

You could print a calendar once and use its monthly layout indefinitely. Imagine that.

A calendar that does not need to be redesigned every January.

The calendar industry might protest, but civilization would probably survive.

There is, however, an important complication.

Those extra days would interrupt the continuous seven-day weekly cycle.

For many people, that sounds like a minor administrative inconvenience.

For others, particularly religious communities whose observances depend on an uninterrupted weekly sequence, it is a fundamental objection.

And that objection would eventually become one of the greatest obstacles to calendar reform.

The Man Who Tried to Fix Time

In 1902, a British railway adviser named Moses B. Cotsworth proposed a calendar that would become known as the International Fixed Calendar.

The idea was straightforward. Thirteen months. Twenty-eight days each. Four weeks per month. Every date permanently assigned to the same weekday.

Cotsworth proposed placing a new month between June and July.

He called it Sol, a reference to the Sun.

The calendar retained the familiar month names while adding Sol as the seventh month.

It was an elegant proposal, particularly for businesses trying to compare monthly expenses, revenues, wages, and production.

And the idea attracted an extraordinarily influential supporter. George Eastman.

Yes, that George Eastman. The founder of Eastman Kodak.

A businessman who helped bring photography to the masses apparently decided that society should also be capable of organizing a year without requiring a different number of days in every month.

And he did more than complain.

Kodak adopted the International Fixed Calendar for internal use in 1928 and continued using it until 1989.

For approximately sixty-one years, one of America’s most famous companies operated internally with a thirteen-month calendar.

The world did not end. Time did not stop. The Earth did not fall out of orbit.

Employees continued working. Products continued being manufactured.

And accountants could compare equal-length reporting periods.

This is particularly fascinating because it demonstrates something important.

A thirteen-month calendar was not merely an intellectual curiosity.

It was a system that a major corporation actually used.

For decades. Yet the rest of the world remained unconvinced.

Sources: U.S. House of Representatives historical archive and the International Fixed Calendar documentation.

Congress Considered Fixing the Calendar—and Then Did What Congress Does Best

Americans may be surprised to learn that calendar reform actually reached Congress.

In 1919, Representative Thomas Schall of Minnesota introduced legislation promoting a thirteen-month calendar.

The proposal returned in subsequent years.

During the 1920s, lawmakers held hearings, business organizations expressed interest, and George Eastman personally advocated calendar reform.

The League of Nations also examined international proposals.

In 1923, it received 185 calendar proposals from 38 countries. Imagine that.

The world had not merely discovered a problem.

It had assembled an international collection of proposed solutions.

One might reasonably believe that humanity was on the verge of making timekeeping simpler.  But then the arguments began.

Religious leaders objected to inserting days outside the weekly cycle.

Businesses worried about contracts and financial obligations.

Lawmakers worried about the consequences of changing something used by virtually every institution on Earth.

And Representative Sol Bloom of New York emerged as a particularly vocal opponent.

Bloom raised a fascinating economic question.

What would happen to salaries and rent?

If workers were paid monthly, would they receive thirteen paychecks instead of twelve?

Would their annual wages remain the same?

Would landlords collect rent thirteen times?

Would insurance companies issue thirteen monthly bills?

Would utility companies suddenly discover an additional opportunity to send invoices?

These were legitimate questions.

A thirteen-month calendar would not automatically create additional income. A fair transition would need to preserve annual contractual amounts and define new payment schedules.

But anyone who has ever dealt with a corporation, landlord, government agency, or insurance company knows how easily the word adjustment can become a euphemism for charging more.

One can almost imagine a landlord announcing:

“Naturally, rent remains $2,000 per month. We would never raise your rent merely because the government added another month.”

And suddenly the tenant is paying $26,000 annually instead of $24,000.

An extra month for the landlord. An extra headache for the tenant.

Such abuses would not be inevitable. They would be precisely the sort of problem legislation would need to prevent.

Nevertheless, the proposed reforms failed to gain sufficient support.

America had investigated making the calendar simpler—and discovered that changing the calendar was considerably more complicated than keeping the old one.

Source: U.S. House of Representatives, How the House Almost Added a 13th Month.

The Moon Has Something to Say About All This

Supporters of thirteen-month calendars sometimes argue that twenty-eight-day months would better align humanity with the natural cycles of the Moon.

It is a lovely thought. Unfortunately, the Moon refuses to cooperate.

The Moon takes approximately 27.3 days to orbit Earth relative to distant stars.

But the cycle from one New Moon to the next takes approximately 29.5 days.

That difference exists because Earth is simultaneously moving around the Sun.

Consequently, thirteen 28-day months would not consistently align with the phases of the Moon.

In fact, a solar year contains approximately 12.37 complete lunar phase cycles.

Nature, it seems, has little interest in making life convenient for accountants.

A thirteen-month calendar would simplify the organization of time, but it would not make our months genuinely lunar.

And this brings us to an important distinction.

A calendar does not need to imitate the Moon perfectly to be useful. It needs to organize human activity efficiently while staying aligned with the seasons.

The current Gregorian calendar accomplishes the second objective extraordinarily well.

The proposed thirteen-month calendar could improve certain aspects of the first.

Neither system can make the Earth and Moon perform their celestial movements in perfect multiples of seven days.

NASA’s explanation of lunar phases confirms the distinction between the Moon’s orbital period and its phase cycle.

And Then There Is Ethiopia…

Here is another interesting fact.

While much of the world regards twelve months as an unavoidable characteristic of civilization, Ethiopia uses a calendar containing thirteen months.

Its system is different from the International Fixed Calendar.

Twelve Ethiopian months contain thirty days each.

The thirteenth month contains five days, or six during a leap year.

And the Ethiopian calendar’s year numbering differs from the Gregorian calendar by approximately seven or eight years.

In other words, an entire country has maintained a calendar with thirteen months.

Civilization did not collapse. People still celebrate birthdays, conduct business, observe religious holidays, and keep appointments.

Of course, Ethiopia’s calendar is not proof that the International Fixed Calendar would work everywhere.

The two systems are fundamentally different.

But it does demonstrate that twelve months are not some unalterable law of nature.

The Earth does not know what month it is. We invented the labels.

Then we became so attached to them that changing the labels began to seem impossible.

Business Already Knows the Calendar Is a Problem

Perhaps the most revealing part of this story is that modern businesses have quietly developed alternatives to the ordinary calendar.

Retailers frequently use a 4-5-4 accounting calendar.

Instead of comparing months with inconsistent combinations of weekdays and weekends, the system organizes fiscal periods into four-week, five-week, and four-week segments.

Why?

Because comparing a month containing four Saturdays against one containing five Saturdays can distort sales analysis.

A retail business might appear to perform better simply because the reporting period contains more important shopping days.

The National Retail Federation maintains a 4-5-4 calendar to improve year-over-year comparisons.

The arrangement requires occasional 53-week fiscal years to remain synchronized with the ordinary calendar.

So even our attempts to simplify timekeeping require periodic corrections.

Nevertheless, the business world has effectively acknowledged something that ordinary people rarely consider.

The calendar inherited from ancient civilization is not necessarily the best arrangement for modern accounting.

And businesses have been finding ways around it for decades.

The Hidden Problem: Thirteen Does Not Divide Very Nicely

Before declaring the thirteen-month calendar the greatest invention since indoor plumbing, we should acknowledge a rather inconvenient mathematical detail.

Thirteen is a prime number.

It cannot be divided evenly into two, three, or four months.

Our current twelve-month calendar accommodates four quarters of three months each.

That arrangement is deeply embedded in financial reporting, taxation, contracts, and corporate planning.

Thirteen equal months would simplify monthly comparisons while complicating traditional quarterly divisions.

We could still have four quarters of thirteen weeks each.

But those quarters would no longer contain an equal number of complete calendar months.

This would require changes to reporting conventions and software systems.

Then consider the technological implications.

Every bank. Every airline. Every insurance company. Every hospital.

Every government agency. Every payroll system. Every accounting platform.

Every database that stores dates. Every computer program that assumes there are twelve months in a year.

Every contract written around the meaning of a calendar month.

All would require some degree of evaluation, adaptation, or replacement.

Not necessarily because thirteen months are inherently inferior.

But because the entire modern world has been built around twelve.

The calendar has become what computer programmers call a legacy system.

And as anyone who has worked with old computer systems understands, the problem with a legacy system is not always that it is good.

Sometimes the problem is that so many other systems depend on it that replacing it becomes more expensive than tolerating its defects.

Our calendar may be the oldest example of technical debt in human civilization.

We inherited the original program from Rome.

Julius Caesar issued a major revision.

Pope Gregory XIII released an important patch.

And for more than four centuries, we have been running the updated version.

The user interface is still terrible. But nobody wants to risk breaking the database.

The Real Reason We Cannot Change It

The greatest obstacle to reform may not be mathematics, religion, economics, or technology considered individually.

It may be something much more fundamental.

Human civilization operates through shared agreements.

Money works because we agree it has value.

Language works because we agree that words have meanings.

Traffic lights work because we agree that red means stop.

And calendars work because billions of people agree on what day it is.

Changing any one of these arrangements requires enormous coordination.

Imagine attempting to convince every country on Earth to adopt a different number of months.

Some would support it. Others would oppose it. Some would demand exemptions.

Some would insist that their traditional holidays remain on their familiar dates.

Others would argue about the name of the thirteenth month.

Religious organizations would raise concerns about the continuity of the weekly cycle.

Businesses would calculate transition costs.

Software developers would begin quietly reconsidering their career choices.

Politicians would form committees.

Committees would schedule hearings.

Hearings would require reports.

Reports would recommend further hearings.

And eventually, after spending several billion dollars studying how to simplify the calendar, the government would announce that the issue required another five years of investigation.

All while using the same old twelve-month calendar to schedule the meetings.

There is something almost poetic about that.

Sometimes the Cost of Change Exceeds the Cost of Nonsense

The more one studies calendar reform, the clearer the central paradox becomes.

A thirteen-month calendar offers genuine advantages.

Equal-length months would simplify some accounting comparisons.

Fixed weekdays would simplify recurring schedules.

Uniform four-week periods would make many planning calculations easier.

But the proposal also has disadvantages.

It disrupts the continuous seven-day week unless modified.

It complicates traditional quarterly accounting.

It requires changes to countless systems and agreements.

And it demands international cooperation on a scale that humanity rarely achieves.

The proper question, therefore, is not simply whether thirteen months make more sense than twelve.

The proper question is whether the advantages justify the enormous disruption required to make the change.

It is possible that they do not. And that is what makes this story more interesting than a simple argument about calendar mathematics.

Something can be unnecessarily complicated without being worth the cost of replacing.

Human civilization is full of such arrangements.

Outdated laws. Confusing bureaucracies. Obsolete technologies.

Government programs designed for problems that disappeared decades ago.

Business procedures inherited from employees who retired before the Internet existed.

We continue doing things in familiar ways because the machinery surrounding those traditions has become extraordinarily difficult to change.

Sometimes this is foolishness. Sometimes it is prudence.

And sometimes it is nearly impossible to tell the difference.

Perhaps the Calendar Is Really a Lesson About Human Nature

I began this discussion wondering why we still use twelve months when thirteen equal months appear so much more orderly.

After examining the history, I find the answer considerably more interesting than the original question.

We do not necessarily retain the twelve-month calendar because twelve is the best possible number.

Nor because the ancient Romans possessed some extraordinary mathematical wisdom that modern civilization cannot reproduce.

We retain it because centuries of institutions, religions, businesses, legal traditions, and ordinary human habits have grown around it.

And once enough of civilization depends on something, even an imperfect arrangement can become extraordinarily resistant to improvement.

There is a lesson here that extends far beyond the calendar.

We humans pride ourselves on progress. We celebrate innovation. We admire those who challenge conventional wisdom.

We spend fortunes inventing new technologies to solve old problems.

Yet when someone proposes changing one of the simplest and most familiar systems in our daily lives, our first instinct is often to explain why it cannot be done.

Not why it should not be done. Why it cannot be done. There is a difference.

The calendar also reminds us that an apparent improvement in one area can introduce costs elsewhere. Genuine progress requires understanding both.

Perhaps thirteen months would be better.

Perhaps a different twelve-month calendar would be an even better compromise.

Or perhaps we have already reached the point where the cost of changing the calendar exceeds any practical benefit.

But there is one thing I find difficult to defend.

The notion that our present arrangement must be the best one simply because it is the arrangement we inherited.

That is not reasoning. That is tradition dressed up as logic.

And tradition, while often valuable, is not automatically evidence of wisdom.

For now, we will continue living with September as the ninth month, October as the tenth, and February as the one month that cannot make up its mind.

We will continue printing different calendars every year.

We will continue teaching children rhymes to remember the number of days in each month.

And somewhere, in an accounting office, someone will continue explaining why February’s financial performance cannot be fairly compared with March’s.

Meanwhile, the Earth will continue traveling around the Sun, completely indifferent to what we call the days.

Which leads me to one final observation.

Humanity has learned to split the atom, sequence the genome, and send machines to other planets. But after thousands of years of civilization, we still cannot agree on how to divide a year into months without making a mess of it.

And perhaps that is the finest illustration of human progress I can offer.

We have become extraordinarily skilled at changing the world.

We remain considerably less skilled at changing our minds.