🌡️ ThermalBar

macOS menu bar CPU & GPU temperature monitor - native, color-coded, lightweight, free.

A free Mac temperature monitor that lives in your menu bar. Live CPU temperature, GPU temperature, RAM usage, and power draw - color-coded, no sudo, no Electron. Built for Apple Silicon (M1, M2, M3, M4, M4 Max, M5).

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Why ThermalBar?

Apple hides chip temperature behind private APIs. Most Mac temperature monitors are heavy Electron apps or need sudo every launch, and a full suite like iStat Menus costs money. ThermalBar is a tiny native Swift app - a free, lightweight, menu-bar Mac CPU/GPU temperature monitor that reads sensors directly and shows them as color-coded numbers in your menu bar - nothing else running, no dock icon, no bloat.

• 🟢 Color-coded at a glance - green when cool, orange when warm, red when hot, dark red when critical. Each value colored independently.
• 🌡️ CPU temperature read natively via IOKit - works with zero dependencies.
• 🎮 GPU temperature + power draw (W) via an optional lightweight helper.
• 🧠 RAM usage (%) - live memory pressure right in the menu bar.
• 🪶 Featherweight - pure Swift, no Electron, no background bloat, no dock icon.
• 🔧 Fully configurable - toggle any metric, set your own color thresholds.
• 🔐 No sudo, ever - reads sensors through a private API without root.
• 🚀 Auto-starts on login, stays out of your way.

Install

git clone https://github.com/evilork/thermalbar.git
cd thermalbar
./install.sh

That's it. The installer builds the app, drops it in /Applications, and sets up auto-start. The menu bar numbers appear in a few seconds.

First launch is unsigned - if macOS blocks it, right-click ThermalBar.app in /Applications → Open (one time).

Requirements

• Apple Silicon Mac (M1-M5), macOS 13+
• Xcode Command Line Tools - xcode-select --install
• Homebrew (optional, for GPU temp + power) - the installer auto-installs macmon if present

CPU temperature works out of the box. GPU temperature and power require macmon (handled automatically by the installer).

Configuration

Click the menu bar item to toggle metrics on/off, or edit ~/.config/thermalbar/config.json:

{
  "cpuTemp": { "enabled": true, "thresholds": { "normal": 60, "warn": 75, "high": 90 } },
  "gpuTemp": { "enabled": true, "thresholds": { "normal": 60, "warn": 75, "high": 90 } },
  "power":   { "enabled": true, "thresholds": { "normal": 30, "warn": 55, "high": 80 } },
  "ram":     { "enabled": true, "thresholds": { "normal": 70, "warn": 85, "high": 95 } },
  "intervalSeconds": 3,
  "showLabels": true
}

Field	What it does
enabled	show this metric in the bar
thresholds.normal / warn / high	color cutoffs (°C for temps, W for power, % for RAM)
intervalSeconds	how often to refresh
showLabels	prefix C / G / R before values

Color rule: value < normal → 🟢 · < warn → 🟠 · < high → 🔴 · ≥ high → 🟥 After editing, pick Reload config from the menu.

How it works

• CPU - reads PMU tdie die-sensors directly through IOKit's private HID interface (the same source powermetrics uses), no root needed.
• GPU, power & RAM - a background macmon serve process exposes these over a local HTTP endpoint; ThermalBar reads them on each refresh. If the helper isn't running, those metrics simply hide and CPU keeps working.

Note on GPU temperature: Apple Silicon does not expose a dedicated GPU temperature sensor - CPU and GPU share one die. ThermalBar reports the GPU figure from macmon's averaged die readings, so it reflects the GPU region of the chip.

Uninstall

./uninstall.sh

Removes the app, both launch agents, and config. (Leaves macmon - remove with brew uninstall macmon if you want.)

Support / Donate

ThermalBar is free and open source. If it earned a spot in your menu bar, a tip is hugely appreciated 🙏

Coin	Address
BTC	bc1pd47ssznzl6afr94zdkyk3g504h4l5m9etfg83lnwlsradg7yrrysk2wlt7
LTC	M9hXcyfRfaXajtzNbVV6pJwC5RoFbijfys
ETH	0x6e5afc8583239da03bf3fd21dd7fafe5e65e1670
SOL	FZ6jUxZUpzneTGgv4X7KAXmxjLrVAfksBojnw6mkEuqQ
TRON	TNHjSq6kc4bmt7tX5QGxd1YsGFa2XN62uQ
TON	UQCCFCDL7fDf6WTcEtAluxL9oAN8sKb3awjH7U752Xkzl1XI

License

MIT © evilork

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_{Built for Apple Silicon. Star ⭐ if it's useful - it helps others find it.}

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A free, native alternative to iStat Menus, Stats, Fanny, and Hot - focused on CPU & GPU temperature, RAM usage, and power, right in the menu bar.