Pi Approximation Day 2024 Date. Pi approximation day is observed on july 22 (22/7 in the day/month date format), since the fraction 22⁄7 is a common approximation of π, which is accurate to two decimal places and.  — pi approximation day date in the current year:

 — pi approximation day 2024 will be marked on july 22.  — pi approximation day, or casual pi day, is observed globally on july 22, representing the fraction 22/7 as an approximation of pi, with 22 symbolizing the date and 7.