How to Check Temperature in Linux and Monitor It: lm-sensors, hddtemp, psensor

Linux does not show component temperatures in the system tray out of the box — unlike Windows. But there are significantly more monitoring tools available: from a single terminal command to graphical dashboards with history and notifications.

CPU Temperature via lm-sensors

lm-sensors is the standard set of utilities for reading hardware sensor data. It reads CPU temperature, motherboard, GPU (via NVIDIA/AMD drivers), and voltage levels.

Installation

sudo apt install lm-sensors hddtemp   # Debian/Ubuntu
sudo dnf install lm_sensors hddtemp  # Fedora/RHEL
sudo pacman -S lm_sensors             # Arch Linux

Initial Setup

Before first use, run the sensor detection wizard:

sudo sensors-detect

Answer Y to all questions — the utility will scan i2c/SMBus buses, detect sensors, and identify the appropriate kernel modules.

At the end the wizard will offer to add the found modules to autoload — accept. Then load modules without rebooting:

sudo systemctl restart kmod

Or reboot the system.

Read Sensor Data

sensors

Typical output for an AMD system:

k10temp-pci-00c3
Adapter: PCI adapter
Tctl:         +44.0°C
Tdie:         +44.0°C
Tccd1:        +40.2°C

nvme-pci-0200
Adapter: PCI adapter
Composite:    +37.9°C  (high = +84.8°C, crit = +94.8°C)

Label meanings:

• Tctl — controller temperature (may read 10–27°C higher on Ryzen, this is normal)
• Tdie — actual die temperature
• Tccd1/Tccd2 — chiplet temperatures (multi-die Ryzen CPUs)
• high — warning threshold
• crit — critical threshold above which throttling begins

Continuous terminal monitoring:

watch -n 1 sensors

The watch -n 1 command refreshes output every second. Useful during stress testing — shows temperature rising in real time.

Disk Temperature via hddtemp and smartctl

hddtemp

sudo hddtemp /dev/sda

/dev/sda: WDC WD10EZEX: 34°C

For multiple disks at once:

sudo hddtemp /dev/sd?

smartctl (more reliable method)

smartctl from the smartmontools package reads disk SMART data including temperature:

sudo apt install smartmontools
sudo smartctl -A /dev/sda | grep -i temp

For an NVMe drive:

sudo smartctl -A /dev/nvme0 | grep -i temp

Temperature via sysfs (No Utilities Required)

The Linux kernel exports sensor data through the virtual filesystem /sys. It can be read directly — without installing any additional packages.

List available temperature sensors:

find /sys/class/thermal -name "temp" -o -name "temp_input" 2>/dev/null

Read temperature (value in millidegrees):

cat /sys/class/thermal/thermal_zone0/temp

Output 44000 means 44°C. Convert to readable format:

awk '{printf "%.1f°C\n", $1/1000}' /sys/class/thermal/thermal_zone0/temp

View all zones at once:

for zone in /sys/class/thermal/thermal_zone*/; do
  type=$(cat "${zone}type" 2>/dev/null)
  temp=$(awk '{printf "%.1f°C", $1/1000}' "${zone}temp" 2>/dev/null)
  echo "$type: $temp"
done

GPU Temperature

NVIDIA

nvidia-smi --query-gpu=temperature.gpu --format=csv,noheader

Or with additional data:

nvidia-smi --query-gpu=name,temperature.gpu,fan.speed,power.draw --format=csv

Continuous GPU monitoring every 2 seconds:

watch -n 2 nvidia-smi --query-gpu=name,temperature.gpu --format=csv

AMD

sensors | grep -i "edge\|junction\|mem"

Or use radeontop for detailed monitoring.

Graphical Monitoring via psensor

psensor is a GUI application with graphs, history, and notifications. It runs on top of lm-sensors.

Installation

sudo apt install psensor

Launch

psensors

Or from the system application menu.

The main window shows a table of all sensors with current, minimum, and maximum values. On the right — color-coded real-time graphs. Checkboxes control which sensors appear on the graph.

Setting Thresholds and Notifications

Double-click a sensor → Alarm tab — set thresholds.

When a threshold is reached, psensor shows a desktop notification. Useful during long computations or rendering — no need to keep watching the terminal.

Running psensor in the System Tray

Launch minimized to tray:

psensors --hide-window

Add to autostart: System Settings → Startup Applications → add psensors --hide-window.

Temperature Reference Values

The Tctl value on Ryzen CPUs may read 10–27°C above actual temperature — this is an architectural feature, not overheating.

Quick Reference