Part of macOS
thermalmonitordTemperature
○ Leave it
Watches the Mac’s temperature.
What it is
Tells macOS when to slow things down to keep the Mac cool.
If you stop it
macOS starts it again straight away. Leave it.
The verdict
○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.
In Activity Monitor
thermalmonitord
From Procession’s guide, in the words the app shows.