As weather gets harder to predict, which iPhone weather app is best?

Ask people which app they use most frequently on their phones, and they’re likely to pick one of five types: a messaging app, a maps app, a web browser, a clock app, or a weather app. If they go with a weather app, it could be one of many. In fact, there are so many weather forecasting apps available for the iPhone—hundreds of them—that Apple’s App Store gives them their own category, something that can’t be said for, say, clock apps. While most come from smaller indie developers,...