Android: If you like a little form with your function, Solar is a weather app that offers it in droves. Instead of just displaying the time, temperature and forecast, Solar uses colourful, visual cues so you to give you detailed information in one glance. Then you can swipe in any direction for more information.
The main screen shows you the basics: temperature, time, date and current conditions. The colours on-screen give you a feel for the time of day (sunrise, sunset, midday, overcast, sunny, etc). Swipe down on the main screen to see the three-day forecast for your location. Scroll (not swipe -- hold your finger on the screen and scroll) up to watch the clock spin and show you the full, detailed 24-hour forecast, including animations for rain or snow, and colour changes for sunrise and sunset. Swipe left to switch among saved locations, or to add new cities to track. Double-tap to see the weather in all of your saved cities at once.
Solar is surprisingly snappy and fast, and while it doesn't include things persistent temp in the notifications panel (although Google Now has this covered) or a home screen widget, I was surprised at how well it worked and how fun it was to use. That said, how much you love the look will really indicate whether this is an app you'll use all the time, or once or twice and forget about in favour of something with those missing features. It does source weather information from Weather Underground's "Best Forecast" feature, so it promises accurate forecasts. Plus, the app is completely free and ad-free, with no banners in the way of its beautifully minimal design. Hit the link below to give it a whirl -- it's been available on iOS for a while now, but it made its debut on Android just this week.
Solar (free) [Google Play]