Raspberry Pi - How To Check Temperature

We are assuming you are running Rasbian or Raspberry Pi OS.

You are generally going to want to keep your Raspberry PI below 85 degrees Celsius.
At above 80 degrees Celsius you willl see a thermometer icon on the screen in the uppper right corner.
It will start throttling at around 82 degrees Celsius.

Core temperature (the temperature of the SoC ):

vcgencmd measure_temp

You can also get temperature details from your Raspberry Pi like this:

cat /sys/class/thermal/thermal_zone0/temp

Check for throttling and other details:

vcgencmd get_throttled

Convert the output to binary and check which bits are set:

Bit	Hex value	Meaning
0	1	Under-voltage detected
1	2	Arm frequency capped
2	4	Currently throttled
3	8	Soft temperature limit active
16	10000	Under-voltage has occurred
17	20000	Arm frequency capping has occurred
18	40000	Throttling has occurred
19	80000	Soft temperature limit has occurred

You might get a value like this:

0x50000 = 0101 0000 0000 0000 0000

This would indicate throttling and under-voltage.

Here is how the bits are numbered:

19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	1	0	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

References