You can usually add a weather widget to your lock screen depending on your Android version and phone model. Try going to Settings → Lock Screen → Widgets or Settings → Display → Lock Screen and look for a weather option.
If it’s not built-in, you can download apps like AccuWeather or Google...
You could root your phone, but keep in mind it comes with risks like bricking your device. If you’re not comfortable with that, try using apps like Swift Backup or check if the game supports cloud saves. Good luck.