The Energy Policy Act of 2005 extended daylight saving time (DST) for an additional month beginning in 2007. The start of DST now occurs on the second Sunday in March and ends on the first Sunday in November in the US.
Clocks will be set ahead one hour at 2 a.m. on March 13, 2016 and set back one hour at 2 a.m. on November 6, 2016.
In response to the Uniform Time Act of 1966, each state of the US has officially chosen to apply one of two rules over its entire territory.
Most use the standard time for their zone (or zones, where a state is divided between two zones), except for using daylight saving time during the summer months. Originally this ran from the last Sunday in April until the last Sunday in October. Two subsequent amendments, in 1986 and 2005, have shifted these days so that daylight saving time now runs from the second Sunday in March until the first Sunday in November.
Arizona and Hawaii use standard time throughout the year. However, the Navajo Nation observes DST throughout its entire territory, including the portion that lies in Arizona. But the Hopi Nation, which is entirely surrounded by the Navajo Nation and is entirely in Arizona, does not observe DST.
In 2005, Indiana passed legislation which took effect on April 2, 2006, that placed the entire state on daylight saving time (see Time in Indiana). Before then, Indiana officially used standard time year-round, with the following exceptions – the portions of Indiana that were on Central Time observed daylight saving time. Also, some Indiana counties near Cincinnati and Louisville were on Eastern Time, but did (unofficially) observe DST.
By the Energy Policy Act of 2005, daylight saving time (DST) was extended in the United States beginning in 2007. These changes result in a DST period that is five weeks longer than previously in years where April 1 falls on Monday through Wednesday and four weeks longer than previously in years where April 1 falls on Thursday through Sunday. In 2008 daylight saving time ended at 2:00 a.m. DST (1:00 a.m. ST) on Sunday, November 2, and in 2009 it began at 2:00 a.m. (3:00 a.m. DST) on Sunday, March 8. Wyoming Senator Michael Enzi and Michigan Representative Fred Upton advocated the extension from October into November especially to allow children to go trick-or-treating in more daylight.
Under Section 110 of the Act, the U.S. Department of Energy was required to study the impact of the 2007 DST extension no later than nine months after the change took effect. The report, released in October 2008, reported a nationwide electricity savings of 0.03% for the year of 2007.
An October 2008 study conducted by the University of California at Santa Barbara for the National Bureau of Economic Research found that the 2006 DST adoption in Indiana increased energy consumption in Indiana by an average of 1%. Although energy consumption for lighting dropped as a result of the DST adoption, consumption for heating and cooling increased by 2 to 4%. The cost to the average Indiana household of the DST adoption was determined to be $3.29 per year, for an aggregate cost of $1.7 million to $5.5 million per year.