Everyone prays for black rain in Hong Kong, especially teachers. When the Hong Kong Observatory issues a Black Rain Warning, it basically means everyone gets a day off work. It's one of those rare treats - you walk down to the foyer of the apartment building and there's a big sign reading, "Black Rain. Go back to bed. You don't need to go to work today, big fella," or something like that.
Today, it's really coming down but they've only issued an Amber Rain Warning, which means, "Bad luck. You still have to go to work, but you're going to get drenched."
I prefer black rain.