iPhone 4If you live in the US, don’t rely on your iPhone’s alarm clock to wake you up on time Monday morning.

Apple has failed to fix a Daylight Saving Time bug in the iPhone’s Alarm app that has already disrupted mornings for many users in Europe and Australia. Even though your iPhone’s internal clock may automatically fall back an hour Sunday morning, a bug in the Alarm app causes it to ignore the Daylight Saving change, which in turn leads certain alarms to go off an hour late.

The bug specifically affects repeating alarms that are scheduled to go off on certain days. Alarms set to repeat every day, or one-time alarms, are reportedly unaffected by the bug.

Apple recommends that users delete existing repeating alarms and rely on one-time alarms until after the Daylight Saving change to Standard Time (2 a.m. EST, Sunday morning). After November 7, you can recreate your repeating alarms. The glitch will be fixed permanently in Apple’s upcoming iPhone operating system 4.2 update, which is slated to land later this month.

European users (and some US users, inexplicably) dealt with the Daylight Saving Time bug last week, which gave Apple only a few days to release a fix in time for the US. Still, Apple doesn’t have much of an excuse — users in Australia and New Zealand first reported the bug several weeks ago.

The company likely doesn’t consider the issue big enough to warrant a software patch of its own, but I’m sure many unhappy iPhone owners who rely on the device as their only alarm clock would disagree.


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