So, how exactly do you tell how hot your iPhone is?

Yesterday, I wrote about how heatwave temperatures can damage — even permanently damage — your iPhone's battery. And even if your iPhone escapes damage, it can put your phone into a mode where you can't do much with it until it cools down.

Then I get what an obvious question is, but one I hoped you wouldn't ask.

How do you tell how hot your iPhone is?

You could wait until your iPhone throws up the high-temperature warning, and then, well, you know it's too hot.

That's the only mechanism that Apple offers.

But surely, the iPhone has a built-in temperature sensor, and there must be apps that can read and display that data.

Surely there's an app for that.

Well, I found one, but I had to download and test dozens of apps in order to find one that will display a reading from the temperature sensor.

The one I found is called Battery and charger test, and while this app looks rather simplistic and does display ads (some especially annoying), it also display a temperature, and this seems to be reasonably accurate. I checked the temperature of the iPhone using a thermal camera, and also warmed and cooled the iPhone to monitor temperature changes. 

It seems reasonably accurate, and right now the best we seem to have.

I dug through a few dozen more apps after testing the Battery and charger test, but I couldn't find anything. If you know of another app that gives temperature readings, let me know.

Don't want to bother with an app? I can think of two other methods:

It's a shame Apple doesn't offer up this information, as it could be something that could help users get more life from their battery.