Dark Sky

Pros: Totally re-imagination of the weather forecast app. Beautiful UI and very precise info.
Cons: Doesn’t make it easy to track the weather through multiple locations.

So your weather app says it’s going to rain today. Well, what time is it going to rain, and for how long? How hard is it going to rain? Other weather apps don’t tell you this stuff, but Dark Sky does. As the name suggests, it’s really useful when the clouds gather and you know bad weather is coming.
It uses an intuitive timeline UI to show you the next hour and how much rain you can expect, minute by minute. Swipe to the right and you get something similar for the next 24 hours. It does a great job of helping you understand what temperature and precipitation to expect at what times throughout the day. 
This really is revolutionary. Yahoo weather tells you it’s going to rain tomorrow. Okay. But if it’s only going to rain from 1-5AM, then you don’t really need to take your umbrella to work, do you? Dark Sky has taken the precision approach, and combined it with a wonderfully intuitive UI that is mostly controlled through gestures. The result is fantastic and has been worth the 4 bucks in my humble opinion.

Swipe right all the way and you get the 7-day forecast. No 10-day is available, but 10 day forecasts aren’t usually that accurate anyway.
If you swipe all the way left you’ll get a visual animation showing the precipitation radar graphs over the last 10 days. You can see the clouds sweeping over the ocean toward your location, and the animation ends at NOW so you get a sense of being brought up to the moment. A temperature graph is available as well.
Weather talk is as old as the hills, but Dark Sky manages to cast new light on it with their innovative UI and focus on detail. A full 5-star bravo and highest recommendation from me.
Available for iOS only.