In the US and Canada, a number of public holidays and observances occur on particular weekdays of a month, rather than on specific calendar dates (day of month). This is apparently done in many instances to schedule their occurrence close to a weekend. Unfortunately, the laws defining these holidays usually specify the weekday of a particular calendar month. As a result, the actual occurrence of these holidays is haphazard from year to year, and the intervals between such holidays vary from year to year, making the planning of work, vacation, and academic schedules difficult.
If all these holidays and observances were defined in terms of one specified date, then they would all occur at regular intervals from year to year. I believe that the best date would be the first Thursday of January. In this way, each such weekday holiday would always occur on the same ISO weekday in any given year.
Below is a table showing a list of such holidays and observances, how they are currently defined, and how they could be redefined:
|US Holiday||Canada||Definition||ISO weekdays||Redefinition|
|ML King Day||—||3rd Mon/Jan||W03-1 43%||W04-1 57%||3rd Mon after 1st Thr|
|Presidents Day||Family Day||3rd Mon/Feb||W07-1 14%||W08-1 86%||7th Mon after 1st Thr|
|Mothers’ Day||2nd Sun/May||W18-7 25%||W19-7 75%||18th Sun after 1st Thr|
|—||Victoria Day||Mon before May 25||W21-1 96%||W22-1 4%||20th Mon after 1st Thr|
|Memorial Day||—||Last Mon of May||W22-1 96%||W23-1 4%||21st Mon after 1st Thr|
|Fathers’ Day||3rd Sun/Jun||W24-7 82%||W25-7 18%||23rd Sun after 1st Thr|
|—||Civic Holiday||1st Mon/Aug||W31-1 25%||W32-1 75%||31st Mon after 1st Thr|
|Labor Day||1st Mon/Sep||W36-1 82%||W37-1 18%||35th Mon after 1st Thr|
|Columbus Day||Thanksgiving||2nd Mon/Oct||W41-1 54%||W42-1 46%||40th Mon after 1st Thr|
|Election Day||—||1st Tue after 1st Mon/Nov||W44-2 4%||W45-2 96%||44th Tue after 1st Thr|
|Thanksgiving||—||4th Thr/Nov||W47-4 54%||W48-4 46%||46th Thr after 1st Thr|