Why does the iPhone alarm clock stop and turn itself off?
The
iPhone alarm clock is designed to sound for 15 minutes, after which it mutes itself automatically.
This is by design, intended to prevent the alarm from going off endlessly, in the even that the iPhone owner is unable to attend to the alarm within that time frame.
That iPhone will turn off its alarm clock sound automatically after 15 minutes can be beneficial for some users, but it can also be detrimental to iPhone users who tend to oversleep, or who like to sleep in, because after 15 minutes the alarm will simply turn itself off.
iPhone alarm turning itself off is a feature that can not be disabled (presently, anyway), the only way around this behavior is to set another alarm, for 15 minutes later. Setting a secondary alarm to get around this feature may be desirable for some users, especially if they
rely on a silent vibrating alarm on iPhone since that type of alarm is more subtle than ones that play sounds.