Apple Watch Series 8
My Apple Watch doesn't respond
Solution 2 of 2: The temperature is too high or too low
If the surrounding temperature is too high or too low, it may cause your Apple Watch to not respond or shut down.
Try using your Apple Watch again when you're in an area where the temperature of your surroundings is within the calculated operating temperature of your Apple Watch. See the recommended operating temperature for your Apple Watch on the Apple web page.