Apps with 'CPU temperature' feature

Core Temp is a compact, no fuss, small footprint, yet powerful program to monitor processor temperature and other vital information. .

This is a port to OS X El Capitan 10.11 of MenuMeters by Alex Harper.

Psensor is a graphical hardware temperature monitor for Linux.

This compact utility displays real-time CPU, RAM and disk drives usage meters right on the taskbar notification area, or next to the system clock, that is always visible.