Weather Underground for iPhone is my favorite weather app. I find the maps particularly useful. Today I set off on a ride while dark clouds hovered overhead. A quick look at the Weather Underground maps page tells me that the clouds will soon move on and so I set off on my ride confident that I won't get stuck in rain. Here's the weather front that came through over the last couple of days and is now on it's way to ruin someone else's cycling plans.
Here's a radar shot of the rain that has now passed us.