ATE DAY8 of 420!
Teenagers, amirite? As the story goes, a group of high school students at a California high school in 1971 began meeting up at 4:20pm — a time picked randomly based on the end of after-school activities — to smoke out. As marijuana was illegal in California at that time, the kids started using “4:20” as a code word.
Source: fwweekly.com