If you live in the U.S., at 2:00 AM on Sunday you will need to turn your clock forward one hour--unless you live in Hawaii or outside the Navajo reservation in Arizona. For those who feel that Daylight Saving Time (not Daylight Savings Time) was created specifically to mess with your schedules and confuse your natural sense of time, I have a short history below.
The change to Daylight Saving Time ostensibly allows us to use less energy in lighting our homes by taking advantage of the increasing and later daylight hours. I haven’t really seen any evidence that it saves energy (some studies have found 1% savings), but the data seems to indicate that it does help increase retail sales. Another consequence of Daylight Saving Time is that violent crime is down by 10-13% during Daylight Saving Time.
On the negative side, one study found a significant increase in pedestrian fatalities in the weeks after the clocks are set back in the Fall. One study found a 186% jump in the risk of being killed by a car for every mile walked. It is speculated that drivers go through an adjustment period when dusk arrives earlier.
Daylight Saving Time was instated nation-wide in the United States during World War I. The idea was to save energy for war production by taking advantage of the later hours of daylight between April and October. Our current Daylight Saving Time was created in 1966 when Congress passed the Uniform Time Act which sought to standardize the length of Daylight Saving Time.
In 2007, Daylight Saving Time was extended. Geographer Matt Rosenberg reports:
Daylight Saving Time is four weeks longer since 2007 due to the passage of the Energy Policy Act in 2005. The Act extended Daylight Saving Time by four weeks from the second Sunday of March to the first Sunday of November, with the hope that it would save 10,000 barrels of oil each day through reduced use of power by businesses during daylight hours. Unfortunately, it is exceedingly difficult to determine energy savings from Daylight Saving Time and based on a variety of factors, it is possible that little or no energy is saved by Daylight Saving Time.
The extension of Daylight Saving Time in the Fall was due to intensive lobbying by candy manufacturers who felt that it would increase candy sales for Halloween. Preliminary data showed little real impact on candy sales.
The United States is not the only country in the world to have Daylight Saving Time: approximately 70 countries utilize Daylight Saving Time. Japan, India, and China are the only major industrialized countries which do not utilize it. The European Union standardized Daylight Saving Time in 1996.
Within the United States, only Hawaii and Arizona don’t change times. However, the Navajo Reservation, the largest Indian reservation in the United States, does change. That means if you are driving in Arizona from Flagstaff to Second Mesa on the Hopi Reservation, you start in Standard Time, then change to Daylight Time when you enter the Navajo Reservation, and then back to Standard Time when you cross into the Hopi Reservation.