As a wanna meteorologist and amateur storm chaser this app is just cool. I have become addicted to it.
Using your current location Dark Sky gives you up to the minute information on when it will start raining/snowing.
As a Live Production guy, rain is not my friend. I wish I had this app a few years ago, instead of just guessing when the rain would come.
I recommend grabbing this beautifully designed app before planning your next family picnic or out door church service.