Extremely weird. Here I thought that BOINC was using the system clock & the time zone in the OS you are using. Yet is it?
If you look at my computers, which are in the same room, spaced apart by about 2 metres, it would seem we have a time zone divider running through the flat, right inbetween the two computers as well. ;)
The Windows box runs at UTC + 1 hour, while the Linux box runs at UTC + 2 hours. Both computers show the correct time that it is right here, both are running on GMT + 2 hours in the OS settings. (We're in the Netherlands)
I think Windows works with Local time (which is for Netherlands GMT+1+1 (for summer time)). For Linux there are 2 possibilities : Local time or GMT.
The difference is how the OS stores the time in computer clock.
For example, if it's 17:00 (time you see on your desktop clock), Windows
will store 17:00 and Linux (if configured in GMT mode) will store it as 15:00.
I am not sure at 100% but I think this is the difference.