Monitor your Mac's temperature in real time

You want to know how hot your Mac is right now, not just whether the chassis feels warm. macOS reads dozens of internal temperature sensors and exposes them — you just have to know where to look.

The built-in command

The most reliable native way to read temperatures is powermetrics:

sudo powermetrics --samplers smc -i 1000 -n 1

This prints SMC (System Management Controller) data including:

• CPU die temperature
• GPU die temperature
• Battery temperature
• Fan RPM and target

The -i 1000 flag sets sample interval to 1000ms; -n 1 takes one sample and exits. For continuous monitoring, raise -n (or omit it, and ctrl+C to stop).

What the numbers should look like

For an Apple Silicon Mac in a normal room:

• CPU die at idle: 35-55C
• CPU die at light load: 50-70C
• CPU die at sustained load: 75-95C
• CPU die at thermal limit: 100C+ (throttling kicks in)
• GPU die: typically a few degrees cooler than CPU
• Battery: 30-45C in normal use, higher when charging

Intel Macs run hotter at the same workloads. 90-100C on an Intel MacBook Pro is normal under sustained load; throttling starts around 100-105C.

Continuous monitoring from Terminal

To watch live:

sudo powermetrics --samplers smc -i 2000 | grep -E "(CPU die|GPU die|Fan)"

This filters to just the lines you care about, updating every 2 seconds. Leave it in a Terminal tab during a long workload to see when the chip heats up.

A menubar option

Running powermetrics all day costs CPU itself (a couple of percent, ironic), and the Terminal output is dense. A menubar app reads the same SMC sensors and surfaces them in a tiny strip without the overhead.

Beacon shows live CPU and GPU temperatures, plus fan RPM, in the menubar — alongside CPU load so you can correlate heat with what’s causing it. $14.99 lifetime. Download Beacon if you want temps always visible.

Reading specific sensors

powermetrics shows aggregated data. For named sensors (some Macs have many — SoC die, PMU die, peripheral controllers), tools that query SMC directly can expose more. Most of those granular sensors only matter for hardware-level debugging.

For most users, three numbers tell the whole story: CPU die temperature, GPU die temperature (if you do graphics work), and fan RPM. Anything else is hardware-engineer territory.

When to actually watch temperatures

• During a long compile, render, or encode — to see if you’re throttling
• After running on battery for a while — to see if the chassis is heat-soaked
• When diagnosing fan noise — to confirm it matches the temperature
• When the Mac is in an unusual environment (hot room, sleeve, sun)

Day-to-day, temperatures rarely matter — the Mac handles them. But when something feels off, real numbers beat guessing.