Nice explanation but I directly quoted the article. Karussell provided an explanation at https://news.ycombinator.com/item?id=29794778
> This makes perfect sense if your role is in bookkeeping / accounting / finance. Your life is based on pay periods and not on day-of-year/month. A particular pay day "belonging" to a particular year is a meaningless affectation: people need to get paid every two weeks come hell or high water, and anything that can complicate the smooth running of that process is discarded.
It's not just payrolls, it's also things like deliveries or synchronisation. And saying "monday week 15" (or writing "W15 mon") aside from being short and precise can give a better ground for synchronisation or collision than "April 11th" e.g. the person you're talking to might know that every monday would be an issue and be able to say that that's not an option before even looking it up.
First off, I think you have a typo(?) with the "2023"? Because:
* https://www.epochconverter.com/weeks/2022
The reason(s) why the week system was designed:
> * All weeks have exactly 7 days, i.e. there are no fractional weeks.
> * Every week belongs to a single year, i.e. there are no ambiguous or double-assigned weeks.
> * The date directly tells the weekday.
> * All week-numbering years start with a Monday and end with a Sunday.
> * When used by itself without using the concept of month, all week-numbering years are the same except that some years have a week 53 at the end.
* https://en.wikipedia.org/wiki/ISO_week_date#Advantages
This makes perfect sense if your role is in bookkeeping / accounting / finance. Your life is based on pay periods and not on day-of-year/month. A particular pay day "belonging" to a particular year is a meaningless affectation: people need to get paid every two weeks come hell or high water, and anything that can complicate the smooth running of that process is discarded.
As for the algorithm:
> The ISO 8601 definition for week 01 is the week with the first Thursday of the Gregorian year (i.e. of January) in it. The following definitions based on properties of this week are mutually equivalent, since the ISO week starts with Monday: […]
* https://en.wikipedia.org/wiki/ISO_week_date#First_week