Not really a question about UTC, just verifying my solution to help myself and others

I realize this might seem unimportant to some, but I find many of those who are starting out on Linux run into this issue and hope this post, not only help verify what I've found, but also the new users who are attempting to sync both clocks.

Initially, like many Windows users, I began my journey with a dual boot system. The offset clocks conflict is a known issue between Windows and Linux because UTC is the Linux default and Windows is not. However, after leaving Windows behind I found my BIOS clock and system clock were continually offset, which bothered me.

I read up on the hwclock and datetimectl commands and synchronized my clocks, and still the Local time and RTC time were off. This led me to set rtc to 1 with the timedatectl set-local-rtc 1 to correct the issue between the two, but the returned warning began to both me.

"Warning: The system is configured to read the RTC time in the local time zone.
This mode can not be fully supported. It will create various problems
with time zone changes and daylight saving time adjustments. The RTC
time is never updated, it relies on external facilities to maintain it.
If at all possible, use RTC in UTC by calling
'timedatectl set-local-rtc 0'."

I began more thorough research on the matter, but every Linux tutorial I read on the subject stated I had synchronized my clocks correctly. So why were my hardware and system clocks off if that was the case? I was missing it some where, so I looked up what UTC time actually is. This is when the light bulb went on. Linux assumes the BIOS on any system is set to UTC, so depending on your timezone, the hardware clock in your BIOS will be offset depending on your relation to GMT. This means if you are on the east coast of the US your BIOS clock will be 4 hours ahead of your system time. If you are on the west coast your BIOS will be 7 hours ahead of your system clock.

Am I correct in my assessment of this issue? I realize this is truly nub territory, but it is something that has bugged me for awhile and felt posting a comment on such a trivial matter would receive some brutal dialog...

It is always best to set the hardware clock to UTC. Even in Windows.

That being said, it isn't requirement in either place. The system can manage the offsets.

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The solution is to change the BIOS time to UTC.

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That is what I have done, but had no idea that UTC would set my BIOS ahead. This caused me to believe I had done something wrong when I hadn't. That is why I looked up what UTC actually is and saw the offset, and then felt like a fool for not doing so sooner..

Thank you for the link to the tutorial. Now that I understand UTC is hours ahead of my global location I have no issue with the offset because it is the correct time in correlation to GMT.

I walked away from Windows when 7 came to end of life, and I am never going back. Linux is far more robust and configurable. I regret fearing the learning curve that kept me from Linux for so long. Wanting the ease of use only hindered my progress on my system.


UTC is the "acceptable" equivalent of GMT (i.e. it's exactly the same but removing the reference to Greenwich, which is in London).

As is common for this sort of thing, "I blame the French." They're just sore that the Greenwich meridian became the standard rather than the Paris meridian. :rofl:


It's like any other OS--as short (or as long) as you want it to be. The key is not being afraid to explore, explode stuff, and explore some more. :wink:

I'm all for ease-of-use. I'm old, my fingers don't work so well anymore, and I don't wish to squander the remainder. But ease-of-use is similar to point-and-click--it truly does help to understand what happens in the background when I do so. You'll catch on. :slight_smile:

Did I mention @jonathon is a historian?

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I agree with his assessment of the French lol

French keep metric systems


Something else we have to blame them for... I mean, who would come up with something that made calculations easy ? :joy:

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yes in physics , all is done in metric

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