Most of the United States begins Daylight Saving Time at 2:00 a.m. on the second Sunday in March and reverts to standard time on the first Sunday in November. In the U.S., each time zone switches at a different time.
When in the morning?
In the U.S., clocks change at 2:00 a.m. local time. In spring, clocks spring forward from 1:59 a.m. to 3:00 a.m.; in fall, clocks fall back from 1:59 a.m. to 1:00 a.m. In the EU, clocks change at 1:00 a.m. Universal Time. In spring, clocks spring forward from 12:59 a.m. to 2:00 a.m.; in fall, clocks fall back from 1:59 a.m. to 1:00 a.m.
Many fire departments encourage people to change the batteries in their smoke detectors when they change their clocks because Daylight Saving Time provides a convenient reminder. "A working smoke detector more than doubles a person's chances of surviving a home fire," says William McNabb of the Troy Fire Department in Michigan. More than 90 percent of homes in the United States have smoke detectors, but one-third are estimated to have dead or missing batteries.