Casio G-Shock wrist watches use a radio-controlled time signal broadcast from Fort Collins, Colorado to keep the most accurate time possible. In order for your Casio G-Shock to display the correct atomic time, you must first set the watch to your time zone. Setting the time zone on your Casio G-Shock wrist watch is a simple task that can be completed by choosing the correct City Code for your particular time zone. You can correct the time zone for your Casio G-Shock in less than five minutes.
Press and hold the top left button your Casio G-Shock wrist watch while in regular Timekeeping Mode.
Wait for the City Code on the display to start flashing, indicating that you have entered the correct setting screen.
Use the bottom right button on your Casio G-Shock to highlight the desired City Code for your time zone. Highlight "LAX" for Pacific time, "DEN" for Mountain time, "CHI" for Central time and "NYC" for Eastern time.
Press the top right button on your Casio G-Shock wrist watch to select the correct and highlighted City Code for your time zone.
Press the top left button on your Casio G-Shock wrist watch twice to exit the setting screen and return to regular Timekeeping Mode.