System-wide configurations for local time zone settings are commonly set via configuration files which vary between operating systems. (If your OS is not listed below, consult your man pages to find out how to set the system-wide time zone default for your system.)
Special considerations when running chrooted
A frequent problem occurring for operators who are running their servers chrooted is that they have omitted the time zone configuration files from the chroot environment, resulting in logs which are recorded in whatever time zone the system hardware clock may be set to, generally UTC.
FreeBSD, Linux: /etc/localtime
Solaris: /etc/TIMEZONE and /usr/share/lib/zoneinfo
OSF: /etc/zoneinfo/localtime
AIX: /etc/environment ($TZ)
See also tzselect(1), tzset(3) and zic(8).