Here is a very nice Cydia tweak that which lets you add a great weather widget to your iOS lock screen. The tweak is called Forecast and it has been developed by iOS developer @Stimpy5050. You can download it from the Cydia Store and once you install it, you’ll be able to display the weather along with the time and date, replacing the default lock screen clock. If you want to switch between current weather or weekly forecast, simply swipe side-to-side just like the Notification Center weather widget.
Below is the official description of the app:
Forecast replaces your regular lockscreen clock with an updated iOS5 native weather widget. The updated widget includes the time and date and an icon to let you manually refresh the weather at any time.Forecast is smart enough to reduce data usage by only refreshing on the lockscreen at most every 15 minutes. Additionally, when weather updates are not available, you can still see the last weather and forecast with an unobtrusive icon in the corner to tell you that weather is offline.
Forecast has no settings or application icons. To disable, remove the tweak.
Forecast is copyrighted by dba Technologies, LLC
You can download it from ModMyi repo on Cydia at an introductory price of $0.99.