Display Dual Clocks on the Lock Screen

When you are away from your home time zone, use Dual clocks to display the time of both your home city and current location on the lock screen.

Go to Settings > System & updates > Date & time, enable Dual clocks, and set a Home city. The time of your home city and current location will now both display on the lock screen.

Only one clock will display on the lock screen if your current location is in the same time zone as your home city.