Saturday 14th March 2015 will be a very special Pi Day. One that only comes along once every 100 years!
This year, not only does the month and day of the date (3/14) correspond to the digits in the mathematical constant, the digits in the year do too. If you write the date in the month/day/year format, then the digits of the date 3/14/15 correspond to the first 5 digits of pi: 3.1415. This year’s Pi Day goes a step further at 9:26:53 am and 9:26:53 pm, the date and the time will exactly correspond to the first 10 digits of pi: 3.141592653
Many people are calling this the Pi Second
Pi Day is an unofficial holiday that celebrates the mathematical constant pi (π). It is celebrated on 14th March in countries that follow the month/day date format because the digits in this date (3/14) correspond with the first three digits of π (3.14). In countries that follow the day/month date format, the holiday comes few months later on July 22 and is called Pi Approximation Day. This is because July 22 or 22/7 is the approximate value of π (22/7 = 3.14).