Months aren’t 100% arbitrary. There’s 12.3ish lunar phase cycles in a year. It’s that “bit more” than 12 thing that trips things up though, and why the lunar month was abandoned for arbitrary 12 divisions. But the 12 wasn’t arbitrary… that’s a nod back to those 12 and a bit lunar months.
Months aren’t 100% arbitrary. There’s 12.3ish lunar phase cycles in a year. It’s that “bit more” than 12 thing that trips things up though, and why the lunar month was abandoned for arbitrary 12 divisions. But the 12 wasn’t arbitrary… that’s a nod back to those 12 and a bit lunar months.