Our mail server is set to use the global
standard Greenwich Mean Time (GMT). Since we have users from all over
the world, setting our server to this common standard time is fair to
everyone (and very fair if you happen to live in Greenwich and area).
When in WebMail, you will need to know your local offset from GMT to
calculate the local time a message was sent or received. For example, if
your local time is North American Mountain Daylight Time, your offset
is GMT minus 6 hours (GMT-6). In this example, if a message is stamped
7:00 AM GMT, it arrived at 1:00 AM local time.
Most mail client software will automatically perform this calculation
for you when you download your mail to your workstation. You do need to
set your local time and time zone for this to work correctly.
For more information on GMT and the measurement of time, there is an excellent article at the NIST Physics Laboratory site.