Have each monitor have an optional time zone field. Do not report GMT time. Report local time. It is a burden to have to mentally convert GMT to local time.
Also local time is much more convenient getting the day right. I am 8 hours behind GMT so 1/3 of the time, I have to adjust the date as well to match up time.
While you are at it, allow both 12 (e.g. am/pm) and 24 hour formats as display options