The Mostly Equal Quarters Calendar is an alternative month Gregorian Calendar that equalizes the quarters with a minimal change to the current Gregorian Calendar As Brij Bhushan Vij has pointed out with his Modified Gregorian Calendar (aka Earth Calendar),
moving one day from July to February would be the easiest way to equalize the quarters in the current Gregorian Calendar, such that in a common year each quarter would have 91-91-91-92 days, and every quarter in a common year would thus start on the same weekday,
and have 13 weeks, with the final quarter having one excess day.
This modest reform might be more easily realized if the modified months had alternative month names that ran simultaneously with the current Gregorian Calendar, enabling users to choose either one date name or another for the same day, as with the Alternative
Month Gregorian Calendars described here:
In fact, the same month names used with the Alternative Month Calendars with the same start dates, but with slightly different month lengths, can be used to define the months of the Equal Quarters Calendar, as follows:
Month NameAbbreviationLengthGregorian Start Date
February (Feb)29/30 Feb 1
Primember(Prr) 31Mar 2
Secundil (Scl) 30Apr 2
Tertember(Trr) 31May 2
October (Oct)31Oct 1
Now, Brij Bhushan Vij has proposed that the leap day be moved to the end of June, as well, but if the leap day is kept at the end of February, then there is minimal disruption in the leap years, as well, and the 2nd, 3rd, and 4th quarters in a leap year
would start on the same weekday as well, without the use of any days outside the seven day week.
Thus, in any given year, seven months are identical with the months of the current Gregorian Calendar, except that February has one additional day in any year, and the five modified months only vary by one day from the the corresponding months of the current