Poncho is a dead simple mobile web app for viewing current and next-day weather conditions. It works on Android and iOS, although it's tailored for non-tablet smartphone devices like Android phones, iPhone and iPod Touch. It's a mobile web app instead of a native app, so it may work on even more platforms, but I haven't tested it on anything else. If you go to app.getponcho.com on your device's browser, you can bookmark and/or add the app to your homescreen and run it virtually just like a native app.
It runs mainly on Spine, a lightweight MVC javascript framework for building web applications. Instead of the bloated jQuery, it uses the more lightweight and mobile-geared Zepto framework. It uses YQL (Yahoo Query Language) as the weather API to pull the current weather conditions and also uses HTML5 LocalStorage to store the user's locations. I needed to choose a javascript templating language as an efficient way to display the data. Javascript templates are in Mustache because of it's small size and efficient rendering.
Check out the full blog post on my website
Note: Poncho's weather icons are the awesome Mobydock icons by Wojciech Grzanka