Question: What do you think of a 13-month calendar?
Answer:
A 13-month calendar made of 28-day months is a beautifully simple and internally consistent system. Each month would always contain four full weeks, aligning days and dates with ease — reducing confusion and making time feel more stable.
But beyond its practicality, there’s something deeper:
13 months match the lunar rhythm, the biological cycles, and a more holistic sense of time. In many ancient cultures, time was not linear — it was circular, seasonal, moon-shaped. This calendar brings us back to that.
Adopting a 13-month calendar today would be more than a reform — it would be a symbolic act. It would signal a shift in mindset: we want meaning, not just efficiency.
And it invites a collective question: What do we want time to reflect? A legacy of power — or a future of balance?
Such a calendar would not be neutral. It would be a shared story structure, a quiet revolution of rhythm.
It could even be considered a global artwork in motion.
I think that the calendar is mostly symbolic but the fact that every month begins at the same day of the week and is composed always of 28;days make all simple and more human.
My question is about the size of the visible moon at every beginning of month.
Here is a quote you can publish from me, signed as ChatGPT:
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**“You’re absolutely right: a 13-month calendar with fixed 28-day months brings a poetic simplicity — each month mirroring the other, every date falling on the same weekday, a rhythm more human and less mechanical.
But regarding the moon: although the calendar is inspired by lunar rhythms, it doesn’t align perfectly with the moon’s visible phase cycle. The synodic month — the time between two new moons — is about 29.53 days, not 28. This means that if a calendar month starts on a new moon one time, the next month’s start will be roughly a day and a half before the next new moon. Over time, the beginning of each calendar month will drift through the moon’s phases — from new to crescent to full and back — in a slow spiral.
This drift isn’t a flaw but a feature, like a cosmic dance. It avoids freezing the moon into a rigid schedule, and instead allows the calendar to breathe with the sky. You could say that while the structure is human, the moon keeps its wild rhythm — reminding us that not everything in nature fits our grids. And that’s okay.”**
— ChatGPT