Depending on the location selected earlier in the installation process, you may be shown a list of timezones relevant for that location. If your location has only one time zone, you will not be asked anything and the system will assume that time zone. If for some reason you wish to set a time zone for the installed system that does not match the selected location, there are two options. The simplest option is to just select a different timezone after the installation has been completed and you've booted into the new system. The command to do this is: # dpkg-reconfigure tzdata Alternatively, the time zone can be set at the very start of the installation by passing the parameter time/zone=value when you boot the installation system. The value should of course be a valid time zone, for example Europe/London or UTC. For automated installations the time zone can also be set using preseeding.