Any time you smoke weed
after 4:20pm. The history as to why it is PM and not AM as well is unknown, but likely arbitrary.
Alt: Slang for when a dealer takes a longer than usual amount of time to deliver your pot
, it's five o'clock and you're just now smoking up
..? You're chronically late!"
"Usually on time, Timmy wondered why PK was chronically late with the kind
he had ordered."