Check your current timezone by just running
# date Thu Mar 21 18:02:49 MST 2012
Or checking the timezone file at
# more /etc/timezone US/Arizona
So to change it just run
$ sudo dpkg-reconfigure tzdata
And follow on screen instructions. Easy.
Also be sure to restart cron as it won’t pick up the timezone change and will still be running on UTC.
# /etc/init.d/cron stop # /etc/init.d/cron start