Developer apps cydia launch release StatusbarWeather8, This tweak works with iOS 8. StatusbarWeather8 jailbreak lets you add to weather conditions right next to the time in your Status Bar, or you can replace the carrier text with the weather instead. After installation, you’ll need to enable the tweak in the Settings and you’re all set. It’s a simple tweak and can come in quite handy when you need to know the temperature without opening the Weather app.
If you are interested, then you can free download StatusbarWeather8 iOS 8 from the BigBoss repository in Cydia. To install this program requires a jailbroken device (see if and how you can do the jailbreak to your iPhone by clicking here) and you need an Internet connection to download the package. This tweak is compatible with iOS 8.0 and later versions of the mobile operating system from Apple.