π id one of my favorite numbers (eiπ=0-1 show my favorite numbers, in no order of preference), so you’d think that I’d be a huge fan of π day — but I’m not.
In our normal decimal system, the digits on the left have more significance (higher magnitude, bigger values) than do the numbers to their right. (In π, you have three units, one tenth, four hundredths, etc.) In most other non-uniform numeric systems, such as degrees-minutes-seconds, you still have the left-to-right indicating larger significance to smaller significance: a degree is bigger than a minute, a minute is bigger than a second.
In writing dates like Americans do, there is an odd mixture of significance: month goes first, then day (which is smaller), but then it jumps back up to years (which is bigger than either). And in the MDYHMS order, you then transition back to descending order of significance. It’s the moral equivalent of writing the digits of one million, two hundred seventy-five thousand, three hundred and thirty-seven as 275,337,1. (See also, Wikipedia’s “Endianness” article, in the section about “Middle-endian“)
Europeans are slightly more consistent in their date representation than Americans, in that at least each group is ascending in significance (day < month < year), but it's still backwards.
Further, the it arbitrarily drops digits (this year is 2015, not 15); and it gives more weight to 9am than it would to 11am: 3.14.15 11:26:53 looks like a smaller number (3.1415112653 as a decimal number is less than 3.141592653, even though 11:26:53 is a bigger time than 9:26:53).
And, to add insult to injury, dates are one-based rather than zero-based.
For me, I think it’s much more logical to define π-day as π days into the year. So a fraction of a second beyond 0:00:00 on Jan 1 would be 0 days (plus a fraction of a second); 1 day would be midnight Jan 1-2, and π days into this year would have been at 2015 Jan 04, 03:23:54am.
So Happy π Day everyone; I’m only two months late! 🙂