There are several rumors circulating about how exactly the number "420" became associated with marijuana. Today, 4/20 is a stoner holiday, and "420 friendly" is code for "down to smoke." Here are some of the myths as to how 420 became synonymous with weed:
420 is not a police code related to marijuana in any state, let alone California. In Los Angeles, 420 is the code used for parties and witnesses to traffic collisions. In Las Vegas, 420 is code for a homicide. 420 is used far a wide variety of offenses in the States, but none of them are related to weed.
Bob Dylan wrote a song titled, “Rainy day women #12 and 35,” which is the origin of 420 according to some stoners. In the song, Dylan repeats, “everybody must get stoned” at the end of every verse. 420 (supposedly) comes from multiplying 12 by 35.
Profiling every single chemical compound in cannabis is difficult. Different websites and different researchers give different estimates as to how many chemicals can be found in weed. However, the common consensus is that it is more than 420.
Douglas Adams' beloved Hitchhiker's guide is a hilarious series of books. Reading the books can feel like a trip in and of itself. According to some cannabis enthusiasts, 420 comes from the chapter when a supercomputer named Deep Thought is asked what the answer to "life, the universe, and everything" is. Deep Thought answers, "42." While it may not seem outrageous that the answer to life is weed, this still is not the origin of 420.
The Netherlands does not recognize a specific time for cannabis consumption. However, 420 has become something of an international symbol. Some people do make a point of smoking at a café when 4:20 rolls around in recognition of the symbol.
The term "420" was coined in 1971 in San Rafael, California by five friends who would regularly gather at a wall outside their high school, and therefore became known as The Waldos. The Waldos heard that a certain Coast Guard service member was unable to harvest his cannabis plants near the Point Reyes peninsula coast guard station and abandoned the garden.
The Waldos decided that they would meet up at 4:20, after their various sports practices, to go looking for the weed. They did not find it. However, they kept looking, meeting at 4:20 each time and smoking all the way to the station and the entire time they were looking. They never found the free weed, but 420 continued to be a code they used for everything from "Are you stoned?" to "Do you have any weed?" Their parents and teachers never caught on.
The way the term became popular was through the Grateful Dead. The band often practiced in San Rafael, and one of the Waldos became friends with Phil Lesh, the bassist. The Waldos and the Grateful Dead hung out and smoked together frequently, with the Waldos continuing to use the code 420 around them. The band took the term with them, and it spread through their fanbase.
Eventually, a cannabis-centered magazine called "The High Times" heard the term and started using it in everything they did, causing it to spread. By the '90s, the term was used throughout the country.