In some cases Notification Center stops working properly after jailbreaking iOS 7 with evasi0n. Items in the Today view might disappear, including the current weather which normally appears when Notification Center is displayed. The good news is there's an easy fix to correct the problem.
If you've noticed the Today tab in Notification Center is blank, follow these steps to bring weather back after jailbreaking. First, make sure the Notification Center settings are configured properly to display the weather widget. If current weather information is still missing after checking these settings, perform the fix on your jailbroken device.