Your location is determined via the WiFi & Mobile Network location service. Please make sure that you’ve enabled the location services and WIFI within your phone settings so you can be located easily. Unfortunately some devices save previous locations within the cache, this can easily be solved by restarting your device.
If you are already using Android 6 or higher, please make sure that you have also enabled the permissions for the location service directly in the settings for the app. Please check under Device settings / Apps / WeatherPro / Permissions if the location service is enabled.