Rsync blessing or pain in the a**

I use rsync to backup all of my stuff to a separate hard drive once a week. Not just because Edd breaks a drive about every two days. This is quite nice because I have a image of that drive and if the one breaks I just slide in the backup one and finished. Further once it's copied all the files (first run) it only copies the changed ones every succeeding run. So how does it do this? Rsync takes creation time modified time size and I don't know what (if you don't tell it to use md5 -n) to compare the files. This is a nice way of doing it IF there wasn't this little thing of daylight saving time. So now the clocks have moved I have to copy every single file over because the file on the backup is one hour older than the original one. Of course this happens only once a Year and it is not that big a deal. But it could easily be changed so that rsync uses utc and not the computer time.