A beloved unofficial holiday for many Americans but one you won’t find on most calendars, 4/20, also known as Weed Day, falls on Monday, April 20.
Coincidentally landing on National Cheddar Fries Day and National Pineapple Upside-Down Cake Day, the date is shaping up to be a great day for snack-lovers and munchies-havers alike. With a smorgasbord of food deals from local and national chains to choose from, there’s no shortage of ways to celebrate.
But how did an otherwise random day in April become shorthand for marijuana culture? Over the years, plenty of theories have ranged from police codes to hidden references in classic songs. The most widely accepted origin story is a little more reminiscent of a classic high school experience.
So how did 4/20 become the official-unofficial weed holiday? Here’s what we know.
420 refers to the date April 20, which has come to be known as the unofficial stoner holiday, when marijuana smokers celebrate their love of bud.
The number 420 itself has also become shorthand for marijuana culture, often used as a colloquial reference to the plant and the act of consuming it. The day is also used by activists and supporters to call for broader legalization and federal decriminalization of weed in the U.S. and beyond.
You may have heard some of the most popular rumors that have swirled through the culture zeitgeist over the years: that 420 is the police code for marijuana use; that it refers to the number of active chemicals in weed; that April 20 was Bob Marley’s birthday (it wasn’t); or that it’s a nod to Bob Dylan’s song “Rainy Day Women #12 & 35” (12 times 35 equals 420).
In reality, the origin is much simpler and perhaps less exciting than those theories.
While no one can say for absolute certain, one widely accepted origin traces back to a group of teenagers hanging out after school.
In the early 1970s, five students at San Rafael High School in Marin County, California, would meet after extracurricular activities near a wall at school. The group, eventually called the “Waldos,” simply for the fact that they met by a wall to do their thing, made their official meeting time for 4:20 p.m. and eventually started using “420” as code for smoking.
One of the Waldo members, Dave Reddix, later got work as a roadie for the Grateful Dead, and the band helped to popularize the term, he told Time Magazine. A key moment came in December 1990, when some Oakland Deadheads distributed a flyer inviting people to smoke on April 20 at 4:20 p.m.
A reporter at High Times magazine got hold of the flyer and printed it in 1991, bringing it to the attention of cannabis fans across state lines. The magazine continued using “420” in later publications, solidifying its place in pop culture.
Steve Bloom, the “High Times” reporter who originally received the flyer, later credited the Waldos for originating the term. In a 2013 blog, he wrote that “they wanted people all over the world to get together on one day each year and collectively smoke pot at the same time. They birthed the idea of a stoner holiday, which April 20 has become.”
Looking forward to partaking this 4/20? Make sure you understand the marijuana laws where you live
The legalization of marijuana varies by state, with rules ranging from medical-only use to fully recreational. Currently, at least 24 states and D.C. have legalized recreational use, and several others are weighing changes through legislation or upcoming ballot measures.
Is weed legal where you live? Check our list and map of where recreational and medicinal marijuana is allowed in 2026.