(This doesn't consider the separator)
Cyan - DD/MM/YY
Magenta - MM/DD/YY
Yellow - YY/MM/DD
The other ones are mixes of those two colors, so e.g. the US is MM/DD/YY and YY/MM/DD (apparently).
Also just noticed I didn't attribute this picture, I'll edit my comment.
YYYY-MM-DD is the only acceptable date format, as commanded by ISO 8601.
Glad I can count my own country, Lithuania, among the enlightened.
EDIT: Source of the picture: https://en.m.wikipedia.org/wiki/File:Date_format_by_country_NEW.svg
Which color is which?
(This doesn't consider the separator) Cyan - DD/MM/YY Magenta - MM/DD/YY Yellow - YY/MM/DD The other ones are mixes of those two colors, so e.g. the US is MM/DD/YY and YY/MM/DD (apparently).
Also just noticed I didn't attribute this picture, I'll edit my comment.