With the new theme, the date is a bit odder looking, but is the same way it has been. It is in the international format, so the date is first, then the month, then the year (DD-MM-YYYY). This format is also known as “little endian“, compared to the “middle endian” format normally used in the United States for whatever reasons.
I am tempted to switch to ISO 8601 standards, which is YYYY-MM-DD (big endian). It has the advantage of being an ISO standard, but isn’t really used much outside the scientific and technical communities and Asia. Then again that perhaps most of those are reason enough.
Wikipedia covers date formats fairly well.
All the date formats raises a question when programming. With everyone using different formats, how can you be sure that somebody is inputing the correct format? Error trapping such entries would be hard I would think. If you are pulling data from a database that you didn’t program, and are not clear on the date format it used, things get confusing. If they used a four digit year, you can at least figure out what part of the date is the year, but figuring the month and date may be harder. The only thing I could figure is to scan all the dates, if you see an area that goes past 12, then that is probably the date, unless it goes past 31, where it probably is a two digit year. The size of that section of error trapping code would be nightmarish. Of course that assumes a Gregorian calendar, not Julian or some lunar based colander where things get even harder. Heck even ISO 8601 seems to allow for Julian type dates…
Why different formats evolved I don’t know. I would guess that when the United States was forming, England was using the middle endian format, since Wikipedia says England switched back to little endian around 1900 they may have been using middle endian themselves then. Personally, I think little endian makes the most sense, even if it is different then what we are used to seeing here in the States.