as soon as the BIOS loaded and showed the time, it was “wrong” because it was in UTC
Because you don’t use Windows. Windows by default stores local time, not UTC, to the RTC. This behavior can be overriden with a registry tweak. Some Linux distro installer disks (at least Ubuntu and Fedora, maybe others) will try to detect if your system has an existing Windows install and mimicks this behavior if one exists (equivalent to timedatectl set-local-rtc 1) and otherwise defaults to storing UTC, which is the more sane choice.
Storing localtime on a computer that has more than one bootable OS becomes a particularly noticable problem in regions that observe DST, because each OS will try to change the RTC by one hour on its first boot after the time change.
That’s strange. As far as I can tell from any web searches, every version Windows still defaults to storing local time to the hardware clock and there are no reports of that changing with an update, nor is there any exposed setting control to configure this behavior outside of regedit. If you’re curious enough, you can check the current setting in the registry at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation. Windows maintains the current time as UTC if and only if the RealTimeIsUniversal key is present and nonzero.
I expect it’s more likely some other issue would make the BIOS display an hour that’s inconsistent with your local timezone. For example, maybe a bug in the BIOS, maybe a timezone offset setting within the BIOS, or maybe a dead clock battery.
Because you don’t use Windows. Windows by default stores local time, not UTC, to the RTC. This behavior can be overriden with a registry tweak. Some Linux distro installer disks (at least Ubuntu and Fedora, maybe others) will try to detect if your system has an existing Windows install and mimicks this behavior if one exists (equivalent to
timedatectl set-local-rtc 1) and otherwise defaults to storing UTC, which is the more sane choice.Storing localtime on a computer that has more than one bootable OS becomes a particularly noticable problem in regions that observe DST, because each OS will try to change the RTC by one hour on its first boot after the time change.
That’s a nice theory, it would be a shame if I was only running Windows 10 on my desktop.
Spoiler: I am. No Linux or any other os or bootloader in sight.
That’s strange. As far as I can tell from any web searches, every version Windows still defaults to storing local time to the hardware clock and there are no reports of that changing with an update, nor is there any exposed setting control to configure this behavior outside of regedit. If you’re curious enough, you can check the current setting in the registry at
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation. Windows maintains the current time as UTC if and only if the RealTimeIsUniversal key is present and nonzero.I expect it’s more likely some other issue would make the BIOS display an hour that’s inconsistent with your local timezone. For example, maybe a bug in the BIOS, maybe a timezone offset setting within the BIOS, or maybe a dead clock battery.