Phone too hot on holiday: what the temperature warning switches off and what to do

What an iPhone turns off, in order of how often you notice

Apple designs iPhones for ambient temperatures between 0 and 35 °C. Above that, the phone starts regulating its own temperature, and Apple lists what changes: charging, including wireless charging, slows or stops; the display dims or goes black; the cellular signal can weaken as the radios enter a low-power state; the camera flash or other camera features can be disabled for a while; and some apps run with lower frame rates or take longer.

If you are navigating, the alert reads Temperature: iPhone needs to cool down and the screen switches off, but Apple says turn-by-turn directions carry on by voice and the display lights up again as you approach a turn. Apple also notes that an iPhone showing this message may still be able to make emergency calls.

Samsung and Pixel phones do the same, in two steps

Samsung describes two warnings. At the first, screen brightness and performance are limited, charging stops, running apps close and calls and other features are restricted, except emergency calls, until the phone cools. If the temperature keeps rising, a second warning appears and the phone turns off. Samsung adds that if this happens during an emergency call, the call is not cut by the shutdown.

Google's list for Pixel phones is similar: lower processor performance and charging speed, the camera flash or camera turned off, and mobile data or Wi-Fi partly or fully disabled, including 5G. The phone may enter low power mode, show a warning and finally switch off. On a Pixel 6 or later you can see how warm it is under Settings, Battery, Battery diagnostics, then Phone is very warm.

When the internet goes first, suspect the heat

Because the radios are among the first things a hot phone throttles, the symptom you notice on a beach or a terrace is often no internet, not a warning. Messages stop sending, maps stop loading, and it looks like a problem with your line or your travel eSIM. Before you touch any settings, feel the back of the phone. If it is hot, move it into the shade and wait; reinstalling or deleting an eSIM is never the fix for heat, and deleting a travel eSIM loses it.

Google names the activities that heat a phone fastest, and several are typical of a trip: sharing your connection with another device, uploading or downloading a lot of data, recording high-definition video and long navigation, all worse while charging. If the connection is still dead once the phone is cool, our guide to an eSIM with no internet goes through the usual switches.

On the beach or by the pool

• Keep it in a bag or under a towel in the shade, not face up on the sand or a sun lounger.
• Do not leave long video recordings or photo uploads running in direct sun.
• Turn off the hotspot if nobody is using it.
• Charge it later, indoors, not from a power bank in the sun.
• Keep heavy games for the evening.

Apple's advice for hot conditions includes not leaving the phone in direct sunlight for an extended period and not playing graphics-intensive games there. Google suggests lowering the screen brightness and using Wi-Fi instead of mobile data when you can, which is easier at the hotel than at the beach. Apple also warns that charging inside certain styles of case can generate excess heat, so if it is warm while charging, take the case off.

In the car

Apple says plainly not to leave a phone in a car, because temperatures in a parked car can go beyond its range, and Samsung gives a car in summer as its example of a place not to use or store a phone for long. A phone on the dashboard in full sun, navigating, charging and streaming music all at once is doing all of the things Google lists as heating it up.

Some of that load can be taken off before you set off. Download the route area as an offline map so the phone is not pulling map data all the way; our guide to using your phone as GPS in a rental car covers that and the mount. Mount it where the sun through the windscreen does not hit it directly, and when you stop for lunch, take it with you.

Cooling it down without making it worse

The three manufacturers agree on the method. Apple says to turn the phone off, move it to a cooler place out of direct sunlight and let it cool down. Google says to unplug it, move it somewhere cooler and not use it until it has cooled. Samsung adds closing running apps and letting it cool before charging again. None of them suggests anything faster, so a shady room and a few minutes are the answer.

It is worth doing early rather than waiting for the warning. Apple says that using a device in very hot conditions can permanently shorten battery life, so a summer of phones cooked on dashboards shows up later as a battery that empties faster. Our article on why phones drain faster when travelling covers the rest of the battery side of a trip.