By the Numbers: Daylight Saving Time

We “fall back” – or end Daylight Saving Time – at 2 am on Sunday, Nov. 5 (Guy Fawkes Day in England), and six months later we “spring forward” to Daylight Saving Time. Where did this bizarre manipulation of time originate?


The year that British builder William Willett published his essay “The Waste of Daylight,” in which he proposed advancing clocks 20 minutes at 2 am on Sundays in April to gain more light through the summer, and that the clocks be turned back 20 minutes on Sundays in September. Despite a tireless campaign for its adoption and the support of a young member of Parliament by the name of Winston Churchill, the measure was never passed in Willett’s lifetime. He died in 1915, and in May 1916 Britain passed a Daylight Saving measure to save on resources needed for the war effort.


Daylight Saving Time became federal law in the U.S., also as a wartime conservation effort, and not for farmers, as the myth of DST normally goes.


The U.S. repeals Daylight Saving Time.


The War Time Act reinstated Daylight Saving Time as a way to conserve resources.


An amendment ended the War Time Act for DST in September. States and cities were free to observe it or not, leading to a patchwork of time zones.


After lobbying by the transportation and airline industries that had to deal with confusing time schedules created by the varied times zones throughout the country, Congress enacted the Uniform Time Act, establishing the start of DST on the last Sunday of April and the end on the last Sunday of October.


The U.S. Dept. of Transportation had determined that DST saved roughly one percent in energy usage, so in response to the energy crisis, DST began in January and February, respectively, in 1974 and 1975. In 1976 DST reverted to the times set by the Uniform Time Act.


The Energy Policy Act set the beginning of DST at 2 am on the second Sunday in March and the return to standard time at 2 am on the first Sunday in November, beginning in fall 2007.

1.3 trillion

The number of watt-hours saved nationally by observing DST, which amounts to powering 100,000 households a year. However, that is a national average. Not all regions benefit from DST. A study in Indiana found a one percent rise in residential electricity use caused by observing DST, at a cost of $9 million.


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