Make Windows 7+ use UTC Real-time-clock

win-timezone-information.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation]
     "RealTimeIsUniversal"=dword:00000001

This is preferred if you have a dual-boot system that runs Windows as the alternate OS. Otherwise your RTC will get reset to the wrong time when Windows runs (and Windows will have the wrong idea of the time too, because it assumes RTC is local when it boots).

You also need to turn off the Windows Time Service (which writes to the RTC in local time despite the above registry setting), with this command from a prompt:

sc config w32time start= disabled

To revert:

• set "RealTimeIsUniversal=- (minus) in the registry file and re-import it
• sc config w32time start= demand

In Linux (systemd), you can also set/disable local time in the RTC. Perhaps you want to leave Windows alone and tweak Linux instead? But UTC is recommended if you can:

sudo timedatectl set-local-rtc 1 (enables. 0 disables).

After doing one of these, reboot, and make sure that the RTC is set correctly from the BIOS/UEFI firmware

Here's a command prompt one-liner for the same effect:
reg add HKLM\System\CurrentControlSet\Control\TimeZoneInformation /t REG_DWORD /v RealTimeIsUniversal /d 1

Just a note that you cannot run sc config w32time within a Powershell prompt, it needs to be the true Command Prompt. Alternatively, you can use Invoke-Command to run sc.exe within Powershell.