Yahoo! Weather was released this morning for iOS, and we've gotta say, it's gorgeous. The company has brilliantly tapped it's Flickr community for imagery that's used in the app, along with nice, lightweight typography.
The app pulls in your location after you give it permission to do so, and combining that with the time and weather conditions, it will then select images to show in the background of your location that nearly match all those parameters. If it is nighttime and snowy, you'll likely get an image of a place somewhere near you taken in similar conditions. Pull up on the display, and you get an hourly forecast for the day, as well as a five-day forecast, and other details like wind level, humidity, visibility, weather map, and even sunrise/sunset details. It all looks really good.