i invented my own which i find easier or at least more useful to read, and a requirement is it does sort properly: YYYYMMmonDD

today is 202309sep21

because i use it for filenames, i don't put in extra punctuation, there are enough cues in the format as is. To really see it, imagine scanning a list of files with different dates

it will still collate properly mixed with languages other than english

Maybe I'm not understanding something, but it seems like it would not collate properly with mixed languages:

  202304abr22 - My Spanish appointment
  202304apr15 - My English appointment
  202304avr07 - My French appointment

oh, you make a good point. I'm generally using it for monthly bank statements and whatnot so I'm not looking for fine grained collation, just grouping of "like with like", and i have some international accounts

I like that, and if day of week is relevant:

    20230915sepFRI

Or for a legibility/size tradeoff:

    2023.09.15.sep.fri

All that left is adding the Chinese zodiac year!

    2023.09.05.rab.sep.fri

Now I am just slightly bothered that the abbreviated words don’t form an isomorphic representation to the numeric. :(

    2023.09.05.3watrab.sep.3fri

3rd Friday in September, 3rd Water Hare starting 1903! :)

Yeah, and that's great for storing things in databases. Not for everyday communication. We talk in terms of most relevant to least relevant - the day (or time) is typically most relevant, with the year being least.

It’s also consistent with ordering numbers from highest base to lowest:

    1023 (1000, 100, 10, 1)

    123.456 (100, …, 0.001)

I also like YYYY-MM-DD

To save screen space I often use decimals in file names:

    2023.05.23 Design Summary