This application shows you the weather, splendid insn't it ! :).
However, its objective is not there, its goal is to show how to build such an application in accordance with good Android practices. So you can be sure it is well built , respectful of your battery and your data.
The application code is open source, it is on github : https: //github.com/MathiasSeguy-Android2EE/. It's the Forecast**Rest project.
This application is also the exercice done by Android2EE's trainees during the training, " I equate Android" ( http://www.android2ee.com/Formations-Android/formation-j-assimile-android.html ) .