First off, apologies for that. I am rarely on IRC as I have other teammates handling that realm... but I am here most days!
Is in-line with what @Stiffy has said as it uses the systems tzdata to gather server timezones, however; I did notice upon your bringing this up (thank you by the way) that I forgot to place a variable for date/time within the ajax options that are used for the bandwidth graph.
You can use
dpkg-reconfigure tzdata to reconfigure your servers timezone to something more area appropriate.
I am working on a commit to push the adjustment now.
Here is the commit that fixes this issue. Feel free to run the cli updater
box upgrade or just update from your dashboard to get this patch.