Temperature issues?

What is your Battery Health at Settings > Battery > Battery Health? If it is below 80%, it will need to be replaced. An update will not solve a battery problem that has reached its end of life and you would likely also have a Service Required message in your Battery Settings if that is the case. The battery in the iPhone 14 is expected to last 500 charge cycles before needing replaced, while newer models increased that expectation to 1000 charge cycles.

After any update there are background processes that are performed for about 4 days to index the files and with iOS 27 additional processes are performed to index Siri and Spotlight. This will produce additional heat on the internal components during this time. Some cases on the phone can also reduce the dissipation of the heat and block air flow, that is easy to test without the case.

If your Battery Health is fine and not one that has been replaced by a third battery or purchased refurbished from a third party, then contact Apple for remote diagnostics.

Contact Apple Support - Apple Support

Hi, batteries below 80% health can behave erratically and generate false notifications and warnings in the process.

So, no, it’s not possible to revert to iOS 26.X.X. Apple has never permitted downgrading from a higher iOS version to a lower version.

If you’re convinced it’s the iOS that caused the issue, then patiently wait for iOS 27.2 to be released and/or report the issue to Apple Support. If you’re in the US, please call  1-800-MY-APPLE, or outside the US, consult the support articles below. In Canada, call 1-800-263-3394.

Contact Apple for support and service - Apple Support

Genius Bar Reservation and Apple Support Options - Apple

Have you recently replaced your iPhones battery? What’s the history of your iPhone? Are you the original owner? A non-Apple replacement battery can trigger false alarms/notifications.

Using A 14 pro here, yes after updating iOS 27 , i have also been facing temperature warning issue and even though the phone is cool, surprisingly it wasn't an issue in iOS 26, Although i have also noticed that when i plug in and use the phone while plugged in to charge, i dont get the temperature warning even though the phone gets hot, i honestly wish that Apple take notes and fixes this issue by 27.1 iOS

iPhone 15 Pro

iOS 27.0

Immediately after updating to iOS 27.0, the device frequently triggers the full-screen thermal lockout warning "Temperature: iPhone needs to cool down before you can use it" while physically cold to the touch in an air-conditioned room. This issue never occurred on iOS 26.

Frequent false thermal lockouts making the device unusable.

[Edited by Moderator]

You aren’t paying attention to the issue. He wasn’t having issues with his iPhone when he’s using iOS 26. The problem started after updating to iOS 27. It then means the problem is the update and not some battery issues.

I’m facing the same problem right now. I can’t use my phone for up to 3 minutes without the temperature warning being triggered. I’m fed up right now. How can I revert back to iOS 26?