A Reddit user came up with an unusual model of the calendar. In her 13 months. Each exactly 28 days. The month begins on Sunday and ends on Saturday. Christmas day is not a day of the week, but in leap year there will be two. Thus for each number fixed day of the week.
In fact, this idea is not new, it was invented by Auguste Comte in 1849. There in a leap year extra day off was supposed to appear after the sixth month. But the idea has taken root: it is inconvenient to divide into quarters, disturbed by a continuous series of weeks.