I think, the Gentoo Localization Guide knows the answer:
In most Gentoo Linux installations, your hardware clock is set to UTC (or GMT, Greenwich Mean Time) and then your timezone is taken into account to determine the actual, local time. If, for some reason, you need your hardware clock not to be in UTC, you will need to edit /etc/rc.conf and change the value of CLOCK from UTC to local.
Code Listing 2.1: local vs. GMT clock
(recommended:)
CLOCK="UTC"
(or:)
CLOCK="local"
So, no you need to set your localtime:
In order to keep time properly, /etc/localtime must point to the correct time zone data file. Look around in /usr/share/zoneinfo/ and pick your timezone or a near-by big city.
Code Listing 1.1: setting the timezone
# ln -sf /usr/share/zoneinfo/Europe/Berlin /etc/localtime
# date
Sun Feb 16 08:26:44 CET 2003
Note: Make sure that the three-letter timezone indicator (in this case "CET") is correct for your area.
Note: You can set the value of TZ to be everything after the /usr/share/zoneinfo in your shell rc file (.bash_profile for bash) for a user-level setting. In this case TZ="Europe/Berlin".
Of course you should select the appropriate city for you
Good luck!