Depending on the location selected earlier in the installation process,
you may be shown a list of time zones relevant for that location.
If your location has only one time zone and you are doing a default
installation, you will not be asked anything and the system will assume
that time zone.
In expert mode or when installing at medium priority, you will have the
additional option to select Coordinated Universal Time
(UTC)
as 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 time zone 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 be set to any desired value
using preseeding.