Thinking about getting a new clock...

There it goes again... Previous Post about this: What time is it? I'm behind -- Or am I ahead

Daylight Saving Time (DST) rules changed in 2007 for the first time in more than 20 years. ...

...Your radio controlled clock should automatically implement the DST rules. The WWVB broadcast contains information that tells your clock whether DST or ST is currently in effect... [However,] Some clocks have the old date rule programmed in and do not use the part of the time code which designates whether or not Daylight Saving Time is in effect. These clocks will switch on the wrong date. The time zone or DST ON/OFF function might need to be switched temporarily so the the clock shows the correct hour for the period between the transition dates according to the old rules and the new rules.

...There are a large number of non-radio controlled clocks, marketed under names like "AUTOSET" or "SMARTSET" that have internal firmware that automatically changes the time by one hour on the transition days to and from DST. These clocks do not connect to a NIST time service, and some of them will no longer work properly due to the DST rule change. For example, clocks manufactured prior to the rule change will probably not switch to DST in March, but will wait until April in accordance with the old rule....

What is Daylight Saving Time?
Daylight Saving Time, or DST, is the period of the year when clocks are moved one hour ahead. In the United States, this has the effect of creating more sunlit hours in the evening during months when the weather is the warmest. We advance our clocks ahead one hour at the beginning of DST, and move them back one hour ("spring forward, fall back") when we return to Standard Time (ST). The transition from ST to DST has the effect of moving one hour of daylight from the morning to the evening. The transition from DST to ST effectively moves one hour of daylight from the evening to the morning.

DST was formally introduced in the United States in 1918. Today, most of the country and its territories observe DST. However, DST is not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands and the state of Arizona (with the exception of the Navajo Indian Reservation, which does observe DST).

Daylight Saving Time and time zones are regulated by the U. S. Department of Transportation, not by NIST. However, as an official timekeeper for the United States, NIST observes all rules regarding DST when it distributes time-of-day information to the public.
http://www.nist.gov/physlab/div847/dst.cfm