This is my interpretation of the lyrics:
It's a fiery afternoonA quick Google search later found the actual song Kolohe Kai - "Cool Down":
So hot, so hot
Run run run run
Yeah, the wig is on fire, the date's getting hot; this is my desire, no want to hit this spot, yeaahhh.
I wasn't too far off on the lyrics, but apparently it's the waves that "is on fire" and the day that's getting hot.