It seems that while booting in
persistent live USB, the wrong time (GMT / UTC instead of local) is displayed (at least that's what happens in Lubuntu 12.10).
Answer from HERE
After executing this, ensure the correct timezone was selected, then set this command to be run automatically and non-interactively at startup by adding it to System -> Preferences -> Sessions -> Add -> Command:
Although in Lubuntu I was not able to add new staff to session, the settings made with first command seem persistent.