Yesterday, I got the MacOSX updates for the Daylight Saving Time’s change in the US.

Million of computers will be updated because in accordance with the Energy Policy Act of 2005, Daylight Saving Time has been expanded by three weeks this year. Beginning in 2007, the United States will observe Daylight Saving Time from the second Sunday in March (March 11) until the first Sunday in November (November 4). This represents a shift from ordinary Daylight Saving Time observance in the northern Hemisphere, with the period beginning two weeks earlier and ending one week later.

Why Is Daylight Saving Time Changing?

In an attempt to reduce energy consumption, the US Congress, in section 110 of the “Energy Policy Act of 2005” announced plans to move the start and ending dates of Daylight Saving Time on the grounds that it allows more effective use of natural sunlight, diminishing the need for electric lighting during the “waking day.” All of Canada (except the regions that do not follow daylight saving) will also observe the new period to avoid possible economic losses from confusion with the United States. Bermuda has announced a similar plan. Studies will determine if this change remains permanent.

According to a U.S. Department of Transportation study, Daylight Saving reduces energy by 1% each day. Daylight Saving also saves lives and prevents traffic injuries. The earlier Daylight Saving Time allows more people to travel home from work and school in daylight, which is much safer than darkness. Daylight Saving Time prevents crime as well. Because people get home from work and school and complete more errands and chores in daylight, Daylight Saving Time also seems to reduce people’s exposure to various crimes, which are more common in darkness than in light.

History of Daylight Saving Time
Standard time in time zones was instituted in the United States and Canada by the railroads in 1883, according to the U.S. Naval Observatory. However, it was not established in U.S. law until the Act of March 19, 1918, often called the Standard Time Act. This act also established daylight saving time, a contentious idea then. Daylight saving time was repealed in 1919, but standard time in time zones remained in law. Daylight time became a local matter. It was re-established nationally early in World War II, and was continuously observed from February 9, 1942 to September 20, 1945. After the war, its use varied among states and localities. The Uniform Time Act of 1966 provided standardization in the dates of beginning and end of daylight time in the U.S. but allowed for local exemptions from its observance. The act provided that daylight time begins on the last Sunday in April and end on the last Sunday in October, with the changeover to occur at 2 a.m. local time.

During the “energy crisis” years, Congress enacted earlier starting dates for daylight time. In 1974, daylight time began on January 6, and in 1975 it began on February 23. After those two years the starting date reverted back to the last Sunday in April. In 1986, a law was passed permanently shifting the starting date of daylight time to the first Sunday in April, beginning in 1987. The ending date of daylight time has not been subject to such changes, and has remained the last Sunday in October. With the Energy Policy Act of 2005, the starting and ending dates have once again been shifted. Beginning in 2007, daylight time will start on the second Sunday in March and end on the first Sunday in November.

Too bad that we don’t follow the same in Europe…