I keep telling people that you can make nice, even months if you just have 13 of them but nooooo, 13 is a prime number, you can’t divide it by 2, 3, 4, or 6! Boo fucking hoo, I want every month in the year to start on the same day of the week.

365/13 is 28.07 - what are you doing with the extra day? + leap years too

The last month is 1 day longer (or 2 on a leap year) which resets the sequence. So exactly 4 weeks per month until the end, then new years has a buffer day.