Pi day is celebrated on March 14 of each year. Pi is an irrational number (its value cannot be expressed exactly as a fraction), represented by the Greek letter Π, is a mathematical constant whose value is the ratio of any circle's circumference to its diameter.
The Greek letter phi (φ) represents the golden ratio which is also is an irrational mathematical constant, with a value of approximately 1.6180339887. Unfortunately, the value of of the phi cannot be easily converted to a calendar date.
However, August 13th is a day that can be celebrated by a number of special people around the world.