In our musical musings, we'd say "Oooh it doesn't even sound like The Biebs does it?" but some random on YouTube seems to have summed it up far more profoundly.
"In this song, justin is explaining how he puts up a wall around him. Yellow means happiness, rain means the fame, the money, the girl and the bad times; the coat means a brick wall.
"In other words, he puts on the yellow raincoat to appear happy to the outside world. But once it is off, he is sad again.
"The raincoat heeps him? safe to everything that is happening around him."
What do you think of the song - could it be about Selena or barriers and inner turmoil? Or does he just love a canary coloured Pac A Mac?