Ice Cube's celebration of a day so good he didn't have to use his AK may have been 30 years ago, January 20th, 1992. Website Now I Know'shared a lot of speculation on the 25th possible anniversary, and recalls Ice Cube's really good day. You can recall it too, by watching the video.
To be clear, at no point in the song do the lyrics explicitly mention the day, month, or even year of the events cataloged. But, intentional or not, Ice Cube left a lot of clues about the date of his good day. Add in the sheer number of people who use the Internet, and you're going to find at least one person who spends a good amount of time piecing those clues together and posting it somewhere online. That's what happened here: a few years back, a website named Murk Avenue used its Tumblr to catalog some of those clues.
To start, Murk Avenue noted, Yo! MTV Raps debuted in August of 1988. As Ice Cube was watching that show, the good day must have occurred no earlier than then. And similarly, the song came out in February of 1993 (and was certainly recorded earlier), setting our upper-bound. Next — and the Wikipedia synopsis misses this key clue — Ice Cube notes that his favorite basketball team, the Los Angeles Lakers, defeated the Seattle Supersonics that day. Murk Avenue runs down all the dates on which this happened, and as it turns out, there are only a dozen during the August 1988 to February 2003 time frame. We're well on our way to finding the good day.