Weather or Not recently launched for iOS devices, bringing with it a simple and elegant UI for weather information. Not only will you get at-a-glance weather information, but Weather or Not also integrates with your calendar so you can see the weather forecast for your individual events allowing you to be prepared throughout the day. The app also has an iOS 8 Today Extension as well.
Here are some of the features of Weather or Not:
Beautiful visualizations of temperature, precipitation, wind, humidity, and more
7-day hourly weather graph
Calendar integration -- see weather for your events
Daily notifications for weather reports and forecasts for your upcoming events