The Weather ($0.99) by Clink Apps is a beautiful little weather app that shows you what you want, when you want.
When you start the app, there will be a little animated help box to get you started with using the app. It will show you the basics and disappear once the tutorial is complete. It can come back again, though you need to toggle this in the app settings within the device Settings, which can be a hassle. Choose from Customary (US) or Metric measurement systems from the Settings.
Automatic updating can be turned on as well, which will allow the app to continue updating data in the background when you're not in the app. This is a nice feature to have.
When you're in the app, you can switch between different views just by scrolling left and right: Temperature, Condition, View, Humidity, Map, Wind, 6 Day Forecast, and Alerts.
You can also add your own custom "pages" that display a cluster of up to 6 bits of weather information at a time. At the end of the ribbon (to the right), you will see a + button. Tap it and you can choose from 10 bits of information to place in the 3x2 grid. Drag the icon of one element into the space, for as many elements as you want, not all the cells have to be filled. If you don't fill all the cells, the display will be adjusted to fill up the screen with however many elements you picked. Make sure to hit Done, or Delete if you change your mind.
If you want edit your custom page anytime, just tap the pencil above it. You can add as many pages as you want in order to get the info you need at a glance. I believe that 2 pages should be enough, but I've kept mine to just one.
If you have location services on, then the app will automatically update your location on startup. However, if it's off, you'll need to manually search for a city or zip code to get weather info. The app allows you to view recent cities and favorites (these are manually managed), and can even get the weather info for a contact, assuming you have their address information.
I've only tested the app on the iPhone, but on the iPad, there's a lot more room for everything, thanks to the screen size. The screen is split into a top half and a bottom half, and use an iTunes Cover Flow-like way to scroll through different information screens. Whichever way you go, there's not much that can be wrong about picking up this app.
I think the biggest thing about the app is the customization of information. You can pick and choose what you want and have it all organized neatly one one single screen, with the additional option to view other bits of information if need be.
There was a glitch I came across where sometimes the icons from the new page customization would get 'stuck' on the screen and I would need to restart the app (force quit it from multitasking tray) to get rid of the ghost icons. But it doesn't happen often and only when I'm making a new page and end up deleting it pretty quick (I did this for testing purposes).
Overall, it may not be the single best weather app, but it's a nice one for $0.99. It's worth it for the customization of what you can view on a single screen, and the sleek interface. The icon reminds me of the old Tweetie 2 icon, which was beautiful back in the day.