DST switch cause iOS users jump time zones the pleasures of Daylight Saving Time. The semi-annual clock shift (known as "Summer Time" in the UK and Europe) saves energy on lighting and heating and aligns daylight hours with the times most people are active; unfortunately, the actual change leads to frayed sleep, a brief spike in traffic accidents, and frustration with gadgets that ought to know how to handle leaping an hour forward.
Apple's devices and operating systems are by no means immune to the confounding effects of DST, as we've seen repeatedly over the past few years. Odd behaviors have cropped up including alarm fouls on iOS, mistaken clocks on Snow Leopard and even Siri being confused about when DST actually starts.
This year, despite substantial updates to iOS, there still appear to be a few kinks to work out. Several readers report that rather than jumping forward an hour last night as expected, their iPhone clocks actually shifted in the wrong direction -- back an hour -- because the automatic time zone adjustment went wonky. A reader in Nashville has a phone that thinks he's in Mountain Time; a reader in Florida's phone is convinced it should be on Chicago time. Our colleague Mel Martin lives in Arizona, which mostly does not observe DST at all; nevertheless, his phone (which had automatic time zone settings & location settings on) incorrectly jumped forward one hour.
