When it's supposedly raining in California, but it's more like a thick mist that blows, moves, and soaks you like rain. It's very pansy like rain.
Girl: "I wore short shorts because i thought the marine layer would clear up, now it's raining!"
Boy: "It's not even rain, it's like.. intense mist."
Girl: "Then why am i soaked?"
Other Girl: "It's just Californiaing."