March 12, 2012

History of Daylight SavingsTime

Villagers, here is more than you wanted to know about daylight time!

Starting in 2007, daylight time begins in the United States on the second Sunday in March and ends on the first Sunday in November. On the second Sunday in March, clocks are set ahead one hour at 2:00 a.m. local standard time, which becomes 3:00 a.m. local daylight time. On the first Sunday in November, clocks are set back one hour at 2:00 a.m. local daylight time, which becomes 1:00 a.m. local standard time. These dates were established by the Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).

Not all places in the U.S. observe daylight time. In particular, Hawaii and most of Arizona do not use it. Indiana adopted its use beginning in 2006.

Many other countries observe some form of "summer time", but they do not necessarily change their clocks on the same dates as the U.S.

Daylight time and time zones in the U.S. are defined in the U.S. Code, Title 15, Chapter 6, Subchapter IX - Standard Time.

History of Daylight Time in the U.S.

Although standard time in time zones was instituted in the U.S. and Canada by the railroads in 1883, it was not established in U.S. law until the Act of March 19, 1918, sometimes called the Standard Time Act. The 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 Daylight saving time was repealed in 1919, but standard time in time zones remained in law.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 9 February 1942 to 30 September 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 begin 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 6 January and in 1975 it began on 23 February. After those two years the starting date reverted back to the last Sunday in April. In 1986, a law was passed that shifted the starting date of daylight time to the first Sunday in April, beginning in 1987. The ending date of daylight time was not subject to such changes, and remained the last Sunday in October. The Energy Policy Act of 2005 changed both the starting and ending dates. Beginning in 2007, daylight time starts on the second Sunday in March and ends on the first Sunday in November.

For a very readable account of the history of standard and daylight time in the U.S., see Ian R. Bartky and Elizabeth Harrison: "Standard and Daylight-saving Time", Scientific American, May 1979 (Vol. 240, No. 5), pp. 46-53.


Schubsta said...

Over here in germany, we have roughly the same principle. I forgot the exact dates, but all I know is, that the shifting of one hour is a major disturbance for the biorhythm. For mine at least. Feels like jetlag.

Los Angelista said...

The early start date is one of the worst ideas ever. I think they need to move it back till April. Having this mess begin in March is a nightmare. It took me a month to recover from it last year.

Villager said...

Shubsta - Disturbing for the biorythms and just a pain-in-the-a$$ when u get down to it. Anyhow, I am pleased to see a visitor from Germany. I remain amazed at the number of visitors our blog is getting from Europe...

Los Angelista - I agree with you entirely. As an aside, I notice that MSNBC is talking about Jamiel Shaw's murder. That is encouraging in that it usually doesn't happen. I think that the fact his mother is in Army veteran on duty in Iraq is the reason the MSM is interested more so than normal...

msladydeborah said...

Grrr! I hate this system!
This is one of the most annoying practices in our national society!

I love it when we fall back because that feels natural to my bio-rhythms. But springing ahead is the content of my stress headaches as I wake up and realize I'm running late.

In reality this last change in the start up dates is way off base. It has not saved energy. Which is the reason given for the adjustment of the months. If you wake up in the dark and have to move around you use light to help you. (Unless you live in the O-State and we've had a ______storm.) :-)

I sincerely believe that one of the reasons why we have become a nation of sleep deprived group of people is due to this switching back and forth of time.

Villager said...

Lady D - I can see that this blog post hit a nerve (smile)! I have such a lousy sleep pattern that the extra hour forward or backward doesn't bother me much...