If you're using your iPhone or iPod touch as your primary alarm clock, it might be time to reconsider. In 2010, Apple had well-publicized difficulties with the switchover to Daylight Saving Time. Alarms failed to go off at their proper times, causing thousands of people in the Southern Hemisphere to wake up an hour early and many more thousands in the Northern Hemisphere to wake up an hour late. Now yet another bug has struck Apple's Clock app in iOS: single-use, non-repeating alarms fail to go off at all after New Year's Day.
Just like the Daylight Saving Time bug, living in New Zealand has given me the opportunity to test this bug ahead of time. Strangely, a single-use alarm scheduled to go off at 7:00 AM today went off on time, but now single-use alarms don't work at all. Only alarms set to repeat at least once during the week will work properly. 9to5Mac suggests that the problem will clear up after January 3, and our testing confirms that -- in a couple of days, the alarms are back to normal.
This bug in the Clock app is somewhat less insidious than the Daylight Saving Time bug, which affected repeating alarms. With this New Year's Day bug, you'll still be safe if you've got a repeating alarm set during the work week. Only single-use alarms will fail to go off. I've tested this with alarms created in 2010 and alarms created in 2011, and it makes no difference; all single-use alarms now fail to activate until after 1/3. I've tested this on an iPhone 4 running iOS 4.2.1 -- your experience may differ if you have a different iOS device or software version.
Considering how many things Apple's managed to get right in iOS, it seems really odd that, of all things, it's the Clock app that keeps getting mucked up. Let us know in the comments if any third-party alarm clock apps are experiencing the same issue (though I doubt it). In the meantime, if you've been using your iPhone or iPod touch to wake you up in the morning, it might be a good idea to invest in a cheap standalone alarm clock -- or take off work until Monday.