MacBook Pro, Pro Display XDR will automatically dim when hot
Apple has revealed that the screens on its new 14-inch MacBook Pro, revised 16-inch MacBook Pro, and Pro Display XDR, will limit their brightness under certain circumstances.

It's an automatic feature that applies specifically to the screen technology introduced with the Pro Display XDR, and the Liquid Retina XDR of the MacBook Pro.
According to a new support document, Apple says that as well as automatically dimming the screen, the feature will display a warning triangle in the menu bar. Similarly, Control Center will show an icon of a screen with a small warning triangle to one side.
"[It means that] your display is in low power mode and using limited brightness," says Apple. "This can occur if the ambient temperature of the room is high and you've been playing very bright content for an extended period of time."
So it's a heat-related issue and one of Apple's proposed solutions is that users put their Macs to sleep. "Let your display cool down for 5-10 minutes," the support document says, "then press any key on the keyboard to wake your Mac."
Apple also suggests that for a MacBook Pro, users quit any apps that "could be consuming significant system resources." With the Pro Display XDR, Apple says users should work in the display's "reference mode unless your current workflow requires a specific reference mode."
For both MacBook Pro and Pro Display XDR, Apple further recommends:
Read on AppleInsider

It's an automatic feature that applies specifically to the screen technology introduced with the Pro Display XDR, and the Liquid Retina XDR of the MacBook Pro.
According to a new support document, Apple says that as well as automatically dimming the screen, the feature will display a warning triangle in the menu bar. Similarly, Control Center will show an icon of a screen with a small warning triangle to one side.
"[It means that] your display is in low power mode and using limited brightness," says Apple. "This can occur if the ambient temperature of the room is high and you've been playing very bright content for an extended period of time."
So it's a heat-related issue and one of Apple's proposed solutions is that users put their Macs to sleep. "Let your display cool down for 5-10 minutes," the support document says, "then press any key on the keyboard to wake your Mac."
Apple also suggests that for a MacBook Pro, users quit any apps that "could be consuming significant system resources." With the Pro Display XDR, Apple says users should work in the display's "reference mode unless your current workflow requires a specific reference mode."
For both MacBook Pro and Pro Display XDR, Apple further recommends:
- Lower the temperature in the room
- Close or hide any windows with HDR content
Read on AppleInsider
Comments
The screen dims because the device is too hot, and the next step along the course of reality-based physics is that the device will be permanently damaged by the heat if actions aren't taken to allow it to cool. It may suck that the screen dims, but it would suck more if the device became completely inoperable, wouldn't it? If you find that this is a frequent problem for you, it would probably be advisable if you would find a different place to secure the phone while driving. Perhaps instead of putting it up on the dash in full sunlight, you would do well to use an A/C vent clip during the hot months. Not only would this reduce exposure to IR radiation from the sun, but it would also make use of the A/C to keep it cool even on the hottest days, which would allow the screen to brightly show your GPS guidance all the way to your destination.
People who don't have the tech knowledge to understand that slowing processes to accommodate diminished battery power at peak demand are not going to have the tech knowledge to understand that phone crashes whenever I click this button or start that app is because of the battery being old.
From a customer (dis)satisfaction standpoint, a slowed device is almost always going to be preferable to crashed device. Slowed device means I can still do the things, but my iPhone is getting old and I'm probably going to have to get a new one soon. Crashed device means I can't do the things any more at all, and I need to replace this piece of junk right now, regardless of whether I have the time or saved money, and because I'm really angry about that, I'll probably buy a different brand device. Seriously. When is having a device that cannot carry out certain functions anymore -at all- preferable to one that can, but does so more slowly? How is writing OS code to assure the latter a "stunt"?
Slowed device brings customers into the Apple Store, where staff can and will inform the customer that replacing the battery is an option if they'd rather hold off on buying a replacement. Crashed device is more likely to send the customer to a competitor who will be happy to reaffirm the impression that the iPhone is no good and that a new Android phone would be much better.
Apple definitely went with the preferred method of slow downs instead of crashes and I have no idea how you could argue the opposite. The only thing that Apple absolutely got wrong in this situation is just not being 100% transparent about it and not simply presenting the user with a warning explaining that their battery needs to be replaced.
Edit: Here is a thought experiment for you. Try searching in google for both the listed problems and see what the "typical" responses are. As I said earlier, you are blindsided by your pro-apple mindset in this scenario. Apple was the ONLY one to pull this stunt, caught red-handed and paid the necessary price. No revisionist history on this please.
Second and Third link: 7 reasons, not one to do with an old battery.
Fourth link: nope
Very First Link for "why is my phone so slow", reason number 3 of 6: "Poor battery health"
I enjoyed that "thought experiment," thanks!
It's also worth noting that the above "thought experiment" searches can actually be accomplished on a slowed device, but not so much on one that keeps crashing while you search.