Are there locales or common programs that use YYYY-DD-MM as the date format?

Question

I've often standardized on YYYY-MM-DD as the date format for communicating within a geographically distributed project teams to dispel any ambiguity that might arise from local date formats.

Is it likely that I might run into people who are used to seeing dates as YYYY-DD-MM? Are there programs that use this as a date format?

Answer 1

See "Calendar date" on Wikipedia on the topic - it lists the countries by date/time format.

At first glance it doesn't look like anyone is using YYYY-DD-MM regularly.

Answer 2

yyyy-mm-dd in particular is a subset of the ISO-8601 format.

There is no recognised standard that uses year date month. When year is first, it should always be followed by an appropriate sub-year, be that quarter, month, julian day, etc.

Some advantages to using year-first is that the order also happens to work well for alpha-sorting when used as a text value (such as part of a file name).