Need I really explain at this point? – Weather Lock Screen - Customize your Lock Screen Backgrounds with Weather Forecast Review

Just like everyone else say, this app is terrible and very misleading. Sure it shows you the weather... for the moment you made the wallpaper. Meaning, you'd have to go through the process again to update what the weather says and yes, every time you want to update. It's just not worth downloading.
Review by AvengingWarrior on Weather Lock Screen - Customize your Lock Screen Backgrounds with Weather Forecast.