iPhone keeps dimming in bright sunlight

I’ve been asked about how to keep the iPhone from dimming at the most inopportune time: when there’s bright sunlight hitting the display. That’s when you’d want max brightness and the least amount of dimming possible in order to keep the screen readable and crisp. Instead, the iPhone likes to dim its screen exactly then, which is invariably irritating.

I’ve searched the web but couldn’t find anything useful. I tried everything here but it does not help: IPhone Screen Keep Dimming With Auto-brightness Off? Try These Fixes

To summarize:

  • Auto-brightness is off
  • Night shift is off
  • Low power mode is off
  • True Tone is off

None of the obvious features that affect screen brightness in some way are active.

I have a suspicion that iPhone might throttle screen brightness to limit the generation of heat on the inside of the device (this is a bit hard to verify but I will try). This is just an assumption on my part, inspired by the fact that I cannot explain this behavior otherwise…

Something I’ve noticed: the screen doesn’t dim smoothly but rather with distinct “jumps”, for lack of a better term.

I use an iPhone 13 Pro Max. A friend reported the same issue on his iPhone 13 Pro.

Has anyone here had this issue?

Perhaps low power mode turned on?

Sadly, it’s not (that would have been too easy!). I updated the original post to include a bit more info.

I’ve also seen this on hot days. I made the same assumption - that it’s dimming the screen to prevent overheating.


It’s a response to overheating.


I always wondered the same thing. Thanks for this post.