I think it's definitely less ambiguous because there are no locales (that I know of) that use YYYY-DD-MM, whereas MM-DD-YYYY and DD-MM-YYYY are both quite commo

I think it's definitely less ambiguous because there are no locales (that I know of) that use YYYY-DD-MM, whereas MM-DD-YYYY and DD-MM-YYYY are both quite common. So, with a little bit of experience, if you ever see four digits first you can be 99% sure that the next part of the date is the month. Edit: I also think that you don't need to be involved in tech in any way to be aware of date formats. They show up in all kinds of everyday places like tax documents, bills, cheques, receipts, exams, etc.