Step 1: The fix involves running a script directly on the device itself to force a rebuild of the corrupt file. Launch Cydia, navigate to the Search section then find and install the OpenSSH package.
Step 2: When the OpenSSH package is installed, exit Cydia and load the Terminal app on your Mac or Command Prompt on your Windows PC. Locate the IP address of the affected iOS device by going to Settings > Wi-Fi and then selecting the connected network.
Step 3: In the Terminal / Command window type the following command: ssh root@[IP ADDRESS]. The IP address of the device from the previous step will need to be added. If private authentication keys haven’t already been established then permission will need to be given. TypeYes and then press enter before inputting the administrator password of alpine (or any other if you have changed it for some reason).
Step 4: The computer will now have root SSH access to the iPhone. Copy and paste the following script into Terminal and then press enter.
#!/bin/bash
chmod -x /usr/libexec/mobile_installation_proxy
killall -9 mobile_installation_proxy
rm /var/mobile/Library/Caches/com.apple.mobile.installation.plist /var/mobile/Library/Caches/com.apple.LaunchServices-045.csstore
launchctl stop com.apple.mobile.installd
launchctl start com.apple.mobile.installd
while [ ! -f /var/mobile/Library/Caches/com.apple.mobile.installation.plist ];
do
sleep 1
done
while [ ! -f /var/mobile/Library/Caches/com.apple.LaunchServices-045.csstore ];
do
sleep 1
done
sleep 10
chmod +x /usr/libexec/mobile_installation_proxy
sync
reboot
Step 5: When the code has been entered and ran, the script will run through its process and force the device to reboot. When everything has loaded back up, the stock Weather app should be as good as new.
(Source: Pod2g’s iOS blog)