Monitor Your Mac’s Heat with Temperature Gauge

I spent two years living in Paraguay, where temperatures are scorching hot and air conditioning is practically non-existent. I had my old MacBook with me the whole time, which I routinely had to open up and clean Paraguay’s ubiquitous red dirt out of. Despite my best efforts, it died an early death, and the culprit, a tech later explained, was heat.

Keeping your Mac cool not only extends its life, but also improves performance. There are a few available utilities that help you keep tabs on your computer’s temperature using the built-in sensors that Macs have. Temperature Gauge from Tunabelly Software is the latest of these apps on the scene.

The Basics

The unambiguous name of the app should give you some idea as to what Temperature Gauge does. The app sits in your menu bar, giving you practically real-time information about your computer’s temperature and fan speeds. The app also has a window that can be opened, which gives more detailed stats. Growl alerts can be configured to warn you when your computer is running dangerously hot.


The menubar gives the temperature, either in Fahrenheit or Celsius, as well as the fan speed in RPM. Clicking on these numbers gives you a menu with access to the preferences pane, as well as the option to show the Temperature Gauge window.

The main window shows all of the sensors that Temperature Gauge has access to.

The main window shows all of the sensors that Temperature Gauge has access to.

The window has a wealth of temperature information. By default, you’ll see a listing of all the available sensors. The left column allows you to filter these by internal component. These main categories include the processor, GPU, battery, memory, Thunderbolt connection, and palm rest.

The top of the window also has a readout for the ambient temperature and the average processor temperature. Apparently most Mac laptops don’t have an ambient temperature sensor, so all I got was a “N/A” readout. If this truly is a rare sensor to have, then perhaps it should be removed rather than clutter up the window.

The app will pick up the fans in your system and show you how hard they are working.

The app will pick up the fans in your system and show you how hard they are working.

The right side of the window displays horizontal bars that give you fan speeds. My MacBook Pro has two fans, and it showed both of them. It would be great to see Temperature Gauge give you the option of controlling the speeds. I use Fan Control occasionally when I want to keep my system cooler, and having that functionality built-in to Temperature Gauge would be a natural addition to the feature set.


The preference pane is relatively limited. Under the temperature settings, you can choose to display information in either Celsius or Fahrenheit. The frequency with which the app updates its readings can be changed via a slider to anywhere from one second to one minute. There is also an option to check the hard drive temperature, but has a warning that this can slow down computers with certain drives. I checked that box and didn’t notice any effect on performance, (I use a stock 500 GB Toshiba drive).

You can control if and when you get Growl alerts.

You can control if and when you get Growl alerts.

You also get some control over what the menubar displays. There are three numbers that can be shown: Two temperature readings and the fan speed, all of which can be hidden if you prefer. For the temperature, you choose from any of the aforementioned sensors, or stick with the default average CPU setting. Interestingly, the fan readout allows you to only show one of the fans, though I can’t imagine why you would do that, especially since both fans typically are running at the same RPM.

What makes Temperature Gauge somewhat unique in this category of apps is its integration with Growl. If any single sensor reads above a limit which you set, you’ll get an alert. The release that I reviewed makes the alerts sticky, meaning that they remain on-screen until you close them. An upcoming release allows you to turn that off, though I imagine with an important alert like this, you would probably want to leave the alerts set to sticky, in case you are away from the computer when it pops up.

Comparison to Similar Apps

The best comparison I can draw here is to iStat Menus. I’ve been using iStat Menus for years, and for the most part, it does everything that Temperature Gauge does, and then some. iStat Menus also sits in your menubar, and can be configured to show a variety of stats about your system, from CPU usage to memory, to yes, even temperature.

iStat Menus has much more that it can monitor, and the design is more attractive.

iStat Menus has much more that it can monitor, and the design is more attractive.

What I like about iStat Menus is that you have an incredible level of control over what you see displayed in the menubar. For instance, I use it to keep an eye on my processor which is displayed as pie chart icon and updates nearly in real-time. If you want to show any other categories as well, those icons show up grouped together in your menu bar.

There is, perhaps, an unnecessary amount of information that iStat gives you. I mean, it can even tell you what phase the moon is currently in, (Waxing Gibbous, at the time of this writing). In that way, perhaps some people would prefer the simplicity of Temperature Gauge, which has a more focused feature set.


At $10, Temperature Gauge isn’t an impulse buy (at the time of this writing, the app is on sale for $5). You definitely need to consider whether or not you truly need this 24/7 monitoring. If you are concerned about your computer just melting on you while living in a place like Paraguay, keep in mind that your Mac will shut itself down before it reaches any dangerous temperature. However, if you are concerned about the longevity of your Mac, keeping it cool is important, and a utility like this is worth having.

iStat Menus does have more features and a higher price tag at $16, but I do think the extra features justify the cost. What sets Temperature Gauge apart though is the Growl alerts, which are a welcome addition. Ideally, I would prefer to have this app capable of hiding itself completely and just have the Growl alerts. At present, you can hide the dock icon, as well as the text readouts in the menubar, leaving only the icon in the menubar. But if I were to use this only for alerts of extreme temperatures, I’d like it to be invisible, and cost at least half the price. I would also love to have control over the fans integrated into the app, though this might be beyond the permissions of an app from the Mac App Store.

Do you worry about your Mac’s temperature? If so, do you bother using a monitoring app? What’s your favorite?


A utility for monitoring the temperature and fan speed of your Mac.