Related: Monitor Raspberry Pi DC input voltage
Check Raspberry Pi CPU Temperature:
A light-moderate use Raspberry Pi 2 in an office environment measures in the 40 - 45 ℃ range (no fan, small heatsink, with case).
A red thermometer icon superimposed on the Raspberry Pi display output means the Raspberry Pi is overheating and is throttling the CPU and GPU to avoid self-destruction.
|CPU temperature [C]||icon||throttle|
|80 - 85||CPU|
|> 85||CPU & GPU|
The current Raspberry Pi CPU speed (actual speed, not limits or requested speed) is obtained from
vcgencmd measure_clock arm
The output is in units of Hertz:
The Raspberry Pi CPU clock speed and power consumption is dynamic:
|clock speed [MHz]||Raspi 2||Raspi 3||Raspi 3+|
|100% one or more cores||900||1200||1400|
You can use
crontab -e for setting a schedule to periodically log temperature and CPU frequency.