420 and Marijuana

I’ve heard the number 420 used in relation to marijuana repeatedly but never figured out what it means. I don’t know anybody who does it, so I can’t ask around. What does the number refer to??

From here:

The cite also dispells some of the myths surrounding the name “420”.

Snopes has the answer - although the information in it is pretty much the same as in 1920’s link

Ah, makes sense now. I’ve heard a reference to the time of day.

Thanks, guys.