Temperature without third-party apps

At the time of writing, all the answers involve use of third-party utilities. If you want to find out the temperature without installing anything, use:

$ cat /sys/class/thermal/thermal_zone*/temp
20000
53000
50000
53000
56000
68000
49000
50000

To see what zones the temperatures are referring to use:

$ paste <(cat /sys/class/thermal/thermal_zone*/type) <(cat /sys/class/thermal/thermal_zone*/temp) | column -s $'\t' -t | sed 's/\(.\)..$/.\1°C/'
INT3400 Thermal  20.0°C
SEN1             45.0°C
SEN2             51.0°C
SEN3             57.0°C
SEN4             59.0°C
pch_skylake      77.5°C
B0D4             50.0°C
x86_pkg_temp     51.0°C

The temperatures are stored in Celsius with 3 implied decimal places. sed is used to “prettify” output.

The last temperature is x86_pkg_temp reported at 54.0°C. For the Skylake i7 6700HQ CPU, I used this temperature for Conky display below.

Temperature with Conky

If you don’t mind third-party utilities I like to use Conky–a light weight system monitor.

Conky commands

Within conky the system variable I used to monitor an Ivy Bridge CPU is:

${hwmon 2 temp 1}°C

To monitor a Skylake CPU I used:

${hwmon 0 temp 1}°C

Conky display

The conky display looks like this:

The temperature starts at 72°C with a single CPU running at 100% in turbo mode of 3200 MHz. Then turbo is switched off and temp drops 10°C to 62°C with a non-turbo speed of 2600 MHz. 10 seconds later turbo is turned back on and temperatures immediately spike back up to 72°C.

Controlling Temperature

After knowing your temperature you probably want to control it better. tlp works wonders for keeping system under control. It works with thermald, Intel Powerclamp, Battery vs AC for USB power, etc. Although highly configurable I’ve never had to change the configuration settings for a pleasant Out-Of-The-Box experience. Prior to using it I had all kinds of problems with an IvyBridge laptop overheating all the time. I have it on my new Skylake laptop and the fans NEVER run except when doing Ubuntu 16.04 LTS to 18.04 upgrade.

You can get a very detailed write-up with installation instructions here: Stop cpu from overheating