No, the light cannot be switched off completely. However, the display is very dim in night mode.

If you set the display very low, you will have problems operating the alarm clock. You need the information on the display to operate it. If the display is too dark or completely gone, you can no longer operate the alarm clock. The only thing that helps is a factory reset, which can only be done using the buttons and the display. If you know the button combination, you can perform the reset blindly (following button sequence: [Switch on radio][Menu][<][Select][>][Select][Select]). Better be happy with some brightness.