Local time changed in between two Linux

I have three Linux installed in my computer: CentOS, Ubuntu and Suse Linux.

CentOS is my first choice as home "production" environment, since it looks stable.
But, sometimes I need to boot into Ubuntu, when I come back to CentOS, the local time is always set to UTC time.

Sigh for many months ... and didn't realize that is a problem.

Today chat with my colleague and identify it must be a problem. Google it first time for "Ubuntu change local time ", I get this https://answers.launchpad.net/ubuntu/+question/2939

Similar case to me and follow the instruction to set UTC=NO inside /etc/default/rcS of Ubuntu.

Testing : set correct time in centos, boot up into ubuntu , reboot to centos again.

Wow, computer's local time is not change.


From this little story, I find it the solution is simple once we identified it clearly and gather sufficient facts. we almost close to the answer.

A bit more thinking makes things so different.