When smartphones get too hot they can start to misbehave and may suffer long-term damage. There have even been a few cases where phones have exploded or burst into flame.

The latter is (hopefully) extremely unlikely to happen to you, but troubleshooting your iPhone's overheating problems now should give you some peace of mind, while helping it to operate smoothly. In this article we offer 10 simple tips to cool down a hot iPhone, and make sure it isn't likely to blow up.

For advice applicable to your other Apple devices, see How to fix an overheating MacBook and How to fix an overheating iMac.

Tips to keep an iPhone cool

If your iPhone keeps overheating, you should look into where and how you are using it. These tips will help:

  • Remove the case. Sounds obvious. Is obvious! But this will help.
  • Don't leave it in a car. Temperatures can rise in parked cars quite rapidly. Take the iPhone with you when parked.
  • You may need to avoid direct sunlight entirely if you're somewhere extremely hot. If you're on holiday somewhere fiercely sunny, keep the iPhone in a bag.
  • Avoid playing games. Games, and particularly graphically advanced games, tax the processor, which heats up the device. AR apps can be particularly taxing.
  • Stop using Bluetooth, because it provides an additional source of heat. You can do this from the Control Centre: swipe up and tap the Bluetooth icon.
  • Turn off Location Services. GPS is probably the single function that heats up an iDevice the most. Turn it off using Settings > Privacy > Location Services.
  • Avoid using Maps turn-by-turn directions. This mode generates a lot of heat.
  • Avoid charging until you get somewhere cooler, or the iPhone's had a chance to cool down. Charging heats up the device.
  • Turn on Airplane mode. This turns off GPS, Bluetooth, WiFi and Cellular data. It's in Control Centre: swipe up from the Home or lock screen and tap the plane icon.
  • Turn the iPhone off entirely. It's a bit extreme but if you're worried about overheating then keeping the iPhone switched off when not in use can help. Hold down the Sleep/Wake button and slide to power off the device.

Hopefully these tips will help you to keep the iPhone running at an acceptable temperature. If not, it's possible that there is a more serious fault, and you should make an appointment at Apple's Genius Bar.

How hot should an iPhone run?

All the current iPhones are designed to operate at ambient temperatures of between 0 and 35º C (32 to 95º F). This is usually good for UK users, as our temperature rarely strays far above or below those two points (although in the summer of 2003 it hit 38.5º C and July 2018 threatened the record). iPhone owners in other countries may need to be more cautious.

How to cool down a hot iPhone: Environmental requirements

It's important to note that these temperatures apply to the use of the iPhone. Apple says it's safe to store an iPhone - but not use it - at any temperature between -20 and 45º C (-4 to 113º F).

You should be careful leaving your iPhone outside in the winter (or taking it into an ice bar, we suppose), or in a parked car in the height of summer. Both of these can push the temperature outside of its operating norm.

How to cool down a hot iPhone: Overheating warning

What happens when an iPhone overheats?

When the iPhone overheats severely it will display a warning message that the iPhone "needs to cool down before you can use it". Normally this will be displayed on a black background, although if you're using navigation it will appear as an overlay alert.

To resume use of your device as quickly as possible, turn it off, move it to a cooler environment, and give it a chance to cool down. The following things will happen when your iPhone is in 'cool down' mode:

  • The device stops charging.
  • The display dims or goes black.
  • Cellular radios will enter a low-power state. The signal may weaken during this time.
  • The camera flash is temporarily disabled.

This can be a bit unnerving when you first see it. But aside from the inconvenience of not being able to use the phone temporarily, there are usually no further problems.

If you'd like to read Apple's official line on the subject, take a look at Keeping devices within acceptable operating temperatures.

Do I need to be worried?

Normally not. Apple advises users that it is normal for an iPhone to get warm when performing demanding tasks such as updating, restoring from backup, analysing data (in Photos face tags, for instance) or running an AR app. It should go back to the normal temperature after the task is complete.

Is my iPhone going to explode?

This is very unlikely, but not impossible.

iPhones have been known to overheat to catastrophic levels - on one occasion melting the floor mat in a Florida woman's car - but these have been isolated cases and usually turn out to be the result of misadventure of some kind. The mat-melting iPhone, for instance, had been dropped in a pool some time before.

(If your iPhone is dropped in water and then miraculously recovers, you should still get it checked out. Internal corrosion could cause trouble down the line.)

In March 2017, CCTV footage emerged of an iPhone 6 Plus, which had been taken into a repair shop, being dropped by its panicked owner when it started to billow with smoke; Simon Owen, the proprietor of the shop (in Australia), reported afterwards that "our service counter has a giant hole in it".

How to cool down a hot iPhone: Exploded iPhone

In this case the phone was damaged previously, and the 'explosion' seems to have happened when the owner pressed down on the broken screen to show what was wrong with it. But this was not an unprecedented incident, even at that shop, whose owner said that three years ago a similar mishap happened with an iPhone 5.

"When they blow, they smoke like that because the two chemicals in the battery mix," said Owen. "It sets off a toxic green haze. It set the whole bin on fire."

If you're wondering about exploding phones right now, it's probably because you've heard about Samsung and its overheating (but otherwise excellent, ironically) Note 7 phablet. The batteries in some Note 7 handsets overheated to dangerous levels, to the extent that Samsung recalled the product completely. You can read more about the Samsung Note 7 incident here.

This is alarming stuff, but bear in mind that this affects only this one model in Samsung's smartphone lineup, and none in Apple's iPhone lineup. Rival phone manufacturers sometimes source components - including battery units - from the same suppliers, but there is presently no suggestion whatsoever that this fault will cause problems for Apple or other companies other than Samsung.