Dark Sky used to be the app that you checked if you wanted to be sure a spontaneous rain cloud wouldn't ruin your impromptu bike ride, but when it came to forecasts, it had essentially nothing to offer. Now, as the app enters version 4.0, things have changed drastically.
Dark Sky's classic one-hour forecast remains a focal point of the experience, with the next hour of your local weather displayed as soon as you activate the app. This should help ease any transition gripes that Dark Sky fans may have, as well as give the app a bit of a familiar feel.
Where Dark Sky has really evolved is in its forecast abilities. You can check the upcoming weather for both the next 24 hours as well as the upcoming week, and each day can be broken down to show when precipitation will happen as well as the temperature ranges. It's everything you need when it comes to forecasting, and it's presented in a very iOS 7-flavored manner that looks fantastic.
The other big change to Dark Sky comes in the form of a revamped radar system. You can now travel to any area of the globe with just a tap and zoom in to see exactly where rain or snow is coming down. There's a built-in forecast tool here too, showing precipitation patterns predicted several days into the future. On both my iPhone 5s and iPad mini with Retina display, the app runs smoothly, though its performance on older devices is something I can't vouch for.
At US$3.99, Dark Sky is indeed one of the pricier weather apps out there, but the fantastic design, convenient by-the-minute predictions and powerful forecasting features are more than enough to warrant a purchase. As far as weather apps go, this should be at the top of your list.