Make New Years Day it's own thing, not counted in a month (or just make the new 13th month 29 days long), and continue tacking on leap days to the end of February using the currently established rules.
The length of the year doesn't change and no seasonal regression. It has so many fewer exceptions than our current system that you'd wonder how we ever ended up with a 12 month calendar.
you’d wonder how we ever ended up with a 12 month calendar
13 x 28 = 364
Make New Years Day it's own thing, not counted in a month (or just make the new 13th month 29 days long), and continue tacking on leap days to the end of February using the currently established rules.
The length of the year doesn't change and no seasonal regression. It has so many fewer exceptions than our current system that you'd wonder how we ever ended up with a 12 month calendar.
Roman Empire politics...
Yeah, and what have the Romans ever done for us?
Decided the number of months?
Nah, just have a double leap day every 4 years.