My Proposal For a 13-Month International Fixed Calendar

Hey everybody, lately I've just been obsessed with alternate calendars, specifically the failures of the French Revolutionary Calendar and the amazing (IMO) 13-month International Fixed Calendar. So I've come up with a calendar system that I think is better than the Gregorian Calendar which is currently in use. Ever wonder why people say there's 4 weeks in a month, when in fact February is the only month with exactly 4 weeks but even then that's only true three quarters of the time, but there's also 52 weeks in a year, meaning that there should actually be 13 months in a year? So here is my proposal for a 13-month calendar.

To ease the switchover I've decided to keep the years the same. I don't want something like the French did with the year 1793 being "Year Zero" or something like that. The days of the week also remain the same (10 day weeks may be one of the most stupidest ideas I've ever heard of), however Sunday will be moved to the end of the week (like it is in Europe, I believe) finally making the term "weekend" make sense though will definitely piss off the Christian community, of which I am apart of.

Each month will have 28 days meaning each day of each month will be the same day of the week forever, meaning that the 1st of each month will always be the first day of the week (quite an unfortunate consequence as birthdays will remain on the same day of the week). I've taken the liberty to change up the order of the months around, and rename a couple.

So originally in the Roman Julian Calendar March used to be the first month of the year before January and February were added later. March is the first month of Spring so I believe it being the first month of the year again signifies the "rebirth" of the year with Spring returning once again. January and February will be added to the end of the year for the end of Winter, though since January is named after the ancient Roman god Janus of both beginnings and endings January will be the final month of the year.

I also am not a fan of months being named after individuals (ancient Roman gods are different since they are mythical beings) so I've renamed July and August to their original names Quintilis and Sextilis (*snicker* I'm sure this month will become the but of many jokes about intercourse). I know, I know, I was born on August 12th but can you just imagine the egos of Julius Caesar and Augustus Caesar?

One of the final changes I've made is making it so that the months of Quintilis, Sextilis, September, October, November, and December are the fifth, sixth, seventh, eighth, ninth, and tenth months of the year in order (which is accomplished by having January and February at the end of the year instead of the beginning).

Now in order to make the months add up to 13 and new month must be added. Now in the Cotsworth Plan the 13th month was to be named Sol and be placed in between June and July. I know that some would love this as we would get a 3 month long summer vacation from school with such a system, however with my desire to keep the months with numerical names in order it cannot go here, unless a month like May or June were renamed Sol, which is totally unnecessary, and would potentially complicate the lives of future Martian settlers who would call their "days" sols. Sol could come after December but that makes no sense since it would be in the middle of freaking Winter and it's named after the Sun!

So that still leaves the open slot for the 13th month, which I've decided to put after December, before February, called Undecember. I know, I know, quite on the nose, though it really is a proposed name for a 13th month since it is the Latin word for 11, and so it just makes sense for it to come after December, now the 10th month of the year. There have also been proposals for a 14th month named Duodecember, a 15th month named Tridecember, and even jokes about a totally nonsensical 16th month named Quadecember (found this one on Urban Dictionary). I even considered removing the months of January and February entirely and placing Undecember, Duodecember, and Tridecember at the end of the year, but since January is the named the the god of endings I think it should remain the last month of the year. And I also considered having all 13 months in Latin numerical order (Primilis, Secundilis, Tertilis, Quartilis, etc.) but decided against it and stuck with the original names of the months as those are what we are all mostly used to.

Finally, the day after the last day of the last month of the year, January 28, would be a Year Day, a global holiday which is not a day of the week so that it's all synchronous. On Leap Years there would be a Leap Day either after or before Year Day (whichever makes the most sense). And yes, I know that people born of Year Day and Leap Day will have a lot of annoyances for the rest of their rest of their lives, just as people born on February 29th IOTL. Major holidays like Christmas, Easter, Thanksgiving, and Independence Day for you filthy Americans will be still be on the same day as they were originally even though they technically doesn't make any sense I'm sure people would still want to celebrate their holidays on the days they used to be without having to calculate the new dates.

So here's what I got so far:
Years (BCE-CE)
Remain the same

Days of the week
1. Monday
2. Tuesday
3. Wednesday
4. Thursday
5. Friday
6. Saturday
7. Sunday

Months of the year
1. March (28 days)
2. April (28 days)
3. May (28 days)
4. June (28 days)
5. Quintilis (28 days)
6. Sextilis (28 days)
7. September (28 days)
8. October (28 days)
9. November (28 days)
10. December (28 days)
11. Undecember (28 days)
12. February (28 days)
13. January (28 days)
Year Day/Leap Day (1-2 days)

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My new birthday ITTL: October 28, 2004 (originally August 12th), the new Halloween!🎃 (And yes Halloween is the All Hallow's Eve night before November 1st, which is All Hallow's Day so ITTL Halloween would occur on the last day of October which is now the 28th). To easily calculate significant dates of importance including birthdays just Google what number day of the year is that date (i.e. August 12th is the 224th day of the year) and compare with the new "Jolendar" (credit to @shearsforest). Other dates like Christmas can still be held on the days they are usually IOTL with the Gregorian Calendar system but dates and holidays that are usually shuffled around the month like Thanksgiving and Easter will be consistently on the same day every year.

Any ideas on how this could positively or negatively impact society if this proposed calendar system was implemented on a large scale?
 
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Instead of fiddling around with the order of the months, why not use the 13 constellations of the zodiac to name the months after?
 
Instead of fiddling around with the order of the months, why not use the 13 constellations of the zodiac to name the months after?
There are 13? Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, Pisces. That's 12, just as with the Persian Calendar. What did I miss out as #13?
 
There are 13? Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, Pisces. That's 12, just as with the Persian Calendar. What did I miss out as #13?
Ophiuchus. It's not traditionally considered one of the zodiac constellations, but it technically is one.
 
But Sunday is already on an end, the front end. Like a candle has two ends.

Unfortunately, I don't see this solving the religious objections (Christians are not the only ones with a seven day worship cycle, though they are the most prominent in the west).
The issue is Year Day and Leap Day throw off the seven days. For example: the first year this is implemented, you go to church on January 28th. Do you go next on March 7th (the next Sunday)? Or March 6th (the seventh day after Jan. 28th)?
Also Easter is not a fixed date for most Christians because it is calculated lunarly because the Jewish calendar was lunar (I am oversimplifying, I know), so fixing Easter to a specific date will also cause a lot if religious based complaints.

Unfortunately, the only method I've found that sidesteps the seven day worship cycle issues and have the calendar be perennial is to hold off on leap day long enough to have a whole seven day leap week. Then that leap week can be added as a inter-month week.
 
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