Weather apps often sit in one of two groups. A lot of data in a mundane presentation, or beautiful backgrounds and animations but a lack of deep weather data.
Weather Live has an excellent mix of both. The US$1.99 universal app has detailed forecasts from anywhere in the world. You can set several cities you want to keep track of, and swipe the screen to view them. Animations reflect the current weather at each location, and the app includes cloud, satellite and radar maps. The app can alert you if bad weather that is on the way, and you can set an alert to let you know when the temperature drops below freezing.
Gallery: Weather Live for iOS