How to set temperature warnings to avoid overheat?

Question

Is there a way to set an alarm or something for when my Ubuntu computer is about to overheat?

My computer has some temperature issues, so when it's about to overheat I'd like to turn on an external fan.

Answer 1

You can use psensor to monitor the computer temperature. This is a GUI application that readout the CPU and Mainboard sensors.

sudo apt-get install psensor 

After starting psensor, go to the "Sensor preference Menu", choose your CPU sensor and click on Alarm - Activate Desktop Notifications. You can modify the temperature limit for your needs:

Can also start after login:

Answer 2

System-monitor GNOME extension

You also have system-monitor:

And choose your threshold

AFAIK it just changes the temperature color. No notification or acoustic alarm. There is a feature request about this issue.