This.
And also, it should still be 12 months, just 4 months (December, January, June and July) should have 5 weeks while the other months have 4 weeks.
The last weeks of December and June and the first weeks of January and July then form a special kind of “half months”, where you get a half month salary and pay a half month rent, etc. Christmas and New Years nicely fit in the Jan/Dec two week holiday, which would be 15 days instead of 14.
In a leap year, the June/July half month would be 15 days instead of 14
This way each season/quarter is still equal to 3 months with 13 weeks. And a half year is 6 months with 26 weeks.
Someone mentioned seasonal regression, this solution should solve that.
And the irony of this all… This is very close to how our current calendar started before Caesars fucked it up.
And also, it should still be 12 months, just 4 months (December, January, June and July) should have 5 weeks while the other months have 4 weeks
But they you still have irregularities. Easier to just add Undecimber to the calendar.
You would then lose the ability to divide the year into pieces, since 13 is prime.
No half-yearly, quarterly or bi-monthly rhythm.
Those divisions are already skewed in a 12 month calendar though because the number of days is not similarly divisible:
Half year (6 months) 1st half: 181 days (182 for leap years) 2nd half: 184 days
Quarter year (3 months) 1st quarter: 90 days (91 for leap years) 2nd quarter: 91 days 3rd quarter: 92 days 4th quarter: 92 days
A leap year has 366 days which is evenly divisible by 2 and yet even then a “half year” at the monthly level doesn’t contain half the days of the year. Having uneven yearly divisions in a 13 month calendar would not be a new problem.
