The 'normal' thing with linux (and unix in general) is to have the system clock set to UTC. My understanding is that all NTP servers are set to UTC. That's why it' called Universal Coordinated Time (
in French anyway).
Then you set your local timezone as part of configuring your machine, and UTC is converted to correct local time for time/date display. For Debian based systems there is a good description of what happens at:
I believe you can also set the system clock to local time, but I don't know if things like NTP and auto daylight-saving still work.
Later -- there is a line 'UTC' in file /etc/adjtime on my Debian setup which I think determines that the system is based on UTC. There should be some sort of configuration tool to safely change the setting but I don't know what it is.