There are also many complaints on Apple Support forums that the information on the Apple Watch Ultra screen cannot be read in the dark. The watch’s ambient light sensor cannot calibrate the brightness to a sufficient level.
Although Watch Ultra 2 users attribute this situation to the hardware, the same complaint comes from first generation Apple Watch Ultra owners. Users say the issue is especially noticeable when quickly moving from a bright room to a dark area and if the Wayfinder and Ultra Modular watch faces are set to night mode. Even though the brightness level is manually adjusted in the Settings section of the watch, the readability problem continues. The problem is said to occur after the watchOS 10.0.1 and watchOS 10.0.2 update.
The screen of Apple Watch Ultra 2, introduced with the iPhone 15 series, can reach up to 3000 nits of brightness. Apple says the Watch Ultra is the model with the brightest screen ever. Screen brightness can drop to 1 nits in some conditions.