Whtr is a free universal app (with in-app purchase options) with a fresh take on how weather information should be presented and organized.
The screens are very clean and simple. The app UI is gesture-based, so swiping up brings up the next screen. There is a clever option to drag the current temperature around an arc that represents a clock to show you future temperature predictions. You can also use the same gestures for predictions of air quality.
The free version is quite complete, providing wind speeds, conditions in my favorite cities, sunset and sunrise times, dew point and more. The app covers about a million locations around the world, and using my iPhone's GPS capabilities it had no trouble pinpointing my home location.
There are 2 in-app purchases. The $1.99 purchase adds more features, including adding more than two cities as favorites and providing visibility readouts. An HD Radar upgrade ($2.99) provides a NOAA-sourced radar plot.
Wthr weather forecasts for iOS
I like Whtr. The free version is ad-free, which is very commendable. The extra features are worthwhile, but I'd rather see the radar and other features bundled into a $1.99 upgrade. One bug I noticed was that if I scrolled the interface down to radar, which I hadn't purchased, the app seemed to get stuck and I could not go back to the weather conditions. I had to shut the app down to start again. Also, to get to the city list, you pinch the main screen -- which isn't very intuitive. An icon for that function might save users some frustration.
There's a lot of fresh thinking in Wthr, but don't forget Yahoo Weather (free) or WeatherBug (free and optional in-app purchases to remove ads) which in my view are the two top general weather apps around.
Wthr runs on any iOS hardware that supports iOS 7 or later. It is optimized for the iPhone 5.