Have you ever stopped to appreciate how wonderful the Gregorian calendar we currently use worldwide is? Ruminating pleasantly on its many positive qualities, such as the way each new year starts in the middle of winter, each month contains a nice, round 4 and 1/3 (ish) weeks, and how dates (like the 1st, 15th, or 31st) politely rotate through different weekdays every year so you never get too comfortable.
No?
Perhaps you’re too enchanted by the elegant system we use to remember month lengths: start with 31 in January and alternate between 30 and 31, except for the part where July and August are both 31 for reasons that are definitely not arbitrary, and February, which has 28 days. Usually.
But surely you appreciate the convenience of holidays defined as things like the “fourth Thursday of a month.” Or how about the way Easter, famously easy to locate, occurs on the first Sunday after the first full moon following the spring equinox. This means it can fall anywhere between March 22 and April 25, depending on a mix of astronomy and rules that were standardized in the 4th century and then adjusted again later for calendar drift. In other words: completely intuitive. Well, at least Halloween and Christmas are easy to find. Most likely, instead, you’ve had thoughts more along the lines of:
“Why are they doing this to us?”
“Were they being stupid on purpose?” (spoiler: kind of)
“Who even are ‘they’?”
So let’s start by answering these.
How Did This Happen?
The current calendar was not designed in a well thought out, practical way. It grew into what we currently use through a series of patches. The early Romans were working with something loosely based on lunar cycles and political convenience. Their calendar didn’t even include January and February at first. They just left those two months of winter outside of the system. The year began in March, which, to be fair, is one of the few decisions in this entire story that actually makes sense. Spring starts, the temperature warms, the days lengthen, and life returns. If you were going to pick a place to start the new year, that would be the obvious place to do it. The month names we still use today reflect that original structure:
- September was the 7th month
- October the 8th
- November the 9th
- December the 10th
Later, when January and February were added, the existing months were pushed back by two places. And then we just… kept the names, even after they stopped being correct. And the system itself was also a mess. Months had uneven lengths, and the year didn’t properly match the solar cycle, so it drifted. To fix this, officials would occasionally insert extra days or even whole months. Conveniently, those officials were politicians, so the system was abused to extend terms of office or manipulate deadlines (purposeful stupidity).
Over time, the calendar drifted so far out of alignment with the seasons that something needed to be done. Enter Julius Caesar, who introduced the Julian calendar in 45 BC. This was a major improvement: a solar calendar with 365 days and a leap day every four years. Finally, something resembling structure. Except there were still issues. The year was about 11 minutes too long. That doesn’t sound like much, but over centuries it adds up. By the 1500s, the calendar had drifted about 10 days out of alignment with the seasons. This became a problem because Christian holidays (especially Easter) were tied to seasonal and astronomical events. So in 1582, Pope Gregory XIII introduced the Gregorian calendar. So how did they fix the drift? Simple:
- Skip 10 days to realign with the equinox
- Adjust leap year rules (century years are not leap years unless divisible by 400)
The 10 day skip was a one time fix, and the new leap year rules dramatically reduced drift from then on. And that’s the system we still use. So what we have today is not a clean design. It’s a compromise of Roman politics, astronomical correction, religious requirements, and the fixes made along the way. All stacked on top of each other and never sorted out.
Okay, It Sucks. Why Not Replace It?
People have tried. The most serious attempt at a clean, rational system is the International Fixed Calendar (IFC). The core ideas are very simple:
International Fixed Calendar
- The year has 13 months
- The extra month, Sol, is placed between June and July
- Each month has exactly 28 days (exactly 4 weeks per month)
- Every date always falls on the same weekday, every year
No more wondering what day of the week a date falls on, no more uneven months, and quarters divided neatly into 13 weeks apiece. It’s almost suspicious in its simple regularity, especially if you're an American used to measuring distance with things like 12 inches in a foot and 5,280 feet in a mile. It's more reminiscent of the metric system.
But there are some difficulties that can't be avoided. The actual number of days for the Earth to complete a revolution around the sun is about 365.2422, so there isn’t even an exact number of days. And with the IFC we have 13 × 28 = 364 days. So we need a ‘Year Day’ attached at the end, and we still need to use the leap day system to account for the extra fraction of a day building up every 4 years (4 × .2422 ≈ 1 day). Year Day and Leap Day would not be weekdays and would function as special holidays outside the standard system. Which sounds awesome. Although there is the drawback that birthdays will always be on the same weekday, which will suck for some people. Imagine if your birthday was always on Tuesday for the rest of forever. As for equinoxes and solstices, they cannot be pinned to an exact day, and the variation is already minimal with the current Gregorian calendar and would remain so with the IFC (±1 day).
The Equinoxes and Solstices
The equinoxes are the two points in the year when day and night are roughly equal in length. And the solstices are the two points when the Sun reaches its highest or lowest point in the sky, giving us the longest and shortest days of the year.
- Spring Equinox ~ March20–21
- Summer Solstice ~ June20–21
- Autumn Equinox ~ September22–23
- Winter Solstice ~ December21–22
These are used to define the seasons in the astronomical system. Meteorology uses a simpler system of fixed dates: March 1 (spring), June 1 (summer), September 1 (autumn), and December 1 (winter).
An honorable mention goes to the Ethiopian calendar, which is related to the Coptic calendar and descends from the calendar traditions of ancient Egypt. Similar to the IFC, it has a more regular structure.
The Ethiopian Calendar
The Ethiopian calendar is built very differently from the Gregorian. To summarize its structure:
- The year has 13 months
- The first 12 months have exactly 30 days each
- The 13th month, Pagume, has 5 days (or 6 in a leap year)
- Leap years occur every 4 years
This makes the Ethiopian calendar more regular than the Gregorian one, but it lacks the International Fixed Calendar’s 13 exactly equal months. And with it we still get the rotating weekdays. Also, its year numbering is different from the Gregorian system, so, depending on the date it is 7 or 8 years behind by comparison.
Sadly, the IFC isn't any good at lining up with lunar cycles (approx. 29.53 days). But there isn’t really a way of nicely lining this up under any system, so we let it go. Some interesting things are believed to have come out of this though, one such example is the Rauhnächte, commonly observed in Austria, Germany, and Switzerland.
Rauhnächte
If we divide the days in the solar year by the number of days per lunar cycle, we have 365.2422 / 29.53 = 12.3685. So we see that per year, the moon completes its full cycle 12 times and change. That extra piece in days is 0.3685 × 29.53 ≈ 10.88. So about 11 days, and if we count nights on both ends, it comes out to 12 nights. In Austrian and wider Central European folk belief, the Rauhnächte (roughly pronounced “ROW-nekh-tuh”, say the 'row' rhyming with 'cow'), the 12 mystical nights from December 24 to January 6, are often explained as filling this gap. According to folklore, these nights are a time when the spirits move among us.
So the moon is not very cooperative, but otherwise the IFC would give us a regular, predictable system. Everything becomes easier to plan and track. So why aren’t we using it?
The biggest issue is that treating those extra days as outside the weekly cycle interrupts the continuous seven day week. That’s a dealbreaker for religions built on an unbroken weekly rhythm. Primarily Judaism, Christianity, and Islam (Sabbath / Sunday worship / Friday prayer). So you run into resistance, not because the system fails, but because it conflicts with inherited rules that are treated as untouchable (aka being stupid on purpose). But apart from that, every contract, fiscal system, and schedule would need adjustment, and people would have to relearn a whole new system (which everyone would be very happy to do, of course). So in short, change is hard and religious zealots will persecute you if you try. But we can still dream. So let’s consider what an ideal calendar might look like...
You wake up on March 1st, still a bit hungover from a banger of a 24 hour celebration of Year Day the day before, looking forward to the new year beginning just as the world springs back to life. You sip your first cup of coffee and enjoy, for a moment, the freedom from religiously imposed constraints as you notice the 13 month calendar on the wall, every month exactly 28 days, just as the gods intended. A friend calls and asks if you will be able to see her on her upcoming birthday this year, and you easily know the answer without checking, since it is always on a Saturday. Within weeks the spring equinox arrives, right where you would expect it, soon after the year's beginning, instead of buried awkwardly inside a system that barely acknowledges it. And the moon? She gets to keep her mysterious nature, unable to be parsed perfectly into any system, which is better anyway. This is the calendar we deserve.
Sources
- Doggett, L. E. “Calendars.” In Explanatory Supplement to the Astronomical Almanac, edited by P. Kenneth Seidelmann. University Science Books. Reproduced online by NASA’s Goddard Space Flight Center.
- Richardson, J. Henry. “Calendar Reform.” International Labour Review 16, no. 2 (1927): 233–244.
- Storl, Wolf-Dieter. Die Magie der Sonnenwenden: Rituale und Pflanzenwissen – Bedeutung und Brauchtum rund um die Sonnenwenden. München: Gräfe und Unzer Verlag, 2024.