When you wake up and your hair is just plain awesome, all on its own, for no particular reason. No matter how much it rains, you sweat, or you get punched in the face, your hair remains rad until the end of the allocated 24 hour period.
Dude I'm totally having a rad hair day. We just experienced a Jumanji-level stampede and I still look like David Hasselhoff.
by Beardcore August 08, 2010