Then that is a bug in them, which should be reported at bugs.kde.org. I believe that may be the fault of KSysGuard which provides them with the information however.

As an experiment I added System Monitor - Temperature to my taskbar. It took up as much space as a single icon. It showed temperature in 'C, as expected. I changed my regional settings to show measurements in Imperial and logged out. On re-entering the taskbar icon showed my system temperature in 'F. There is only one sensor available on this laptop. I don't know how the availability of more sensors would affect the size. Perhaps someone else could answer that. So, apart from not issuing warnings, does that not fit the bill?

annew wrote:As an experiment I added System Monitor - Temperature to my taskbar. It took up as much space as a single icon. So, apart from not issuing warnings, does that not fit the bill?

Simply the width taken by plenty of "plasmoïds" in a taskbar, compared to an icon in a systray.

I said "It took up as much space as a single icon." And yes, it was in the taskbar, not the system tray.

system-monitoring-temperature widget do not have digits when they are in the taskbar and it is not easy to undestand what exactly is the temperature from first look.

Yes, you have to hover over it to see the temperature, which is not quite as convenient as being able to simply glance at it.