Martti Kuparinen <martti.kuparinen@iki.fi> writes:

> How should I read these values, i.e. what is the current temperature
> (preferably in Celcius)?

There's no standard mapping. The range is 0-255 and higher values are
"better" and lower values are "worse" in the sense of "closer to
failure", so for a disk, probably "hotter". That the threshold is 0
for temperature seems odd. My desktop reports:

id      value   thresh  crit    collect reliability description
...
194      79      42     no      online  positive    Temperature

You might ask the disk vendor or look for spec sheets that describe
their SMART information if you want to map it to a real temperature.

        - Nathan