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Spring forward, fall back The history of Daylight Saving Time
Daylight saving time (DST)—also summer time in British English— is the practice of advancing clocks during the lighter months so that evenings have more daylight and mornings have less. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn.
Most areas of the United States currently observe daylight saving time (DST), the exceptions being Arizona (except for the Navajo Nation, which does observe daylight saving time), Hawaii, and the overseas territories of Puerto Rico, American Samoa, Guam, Northern Mariana Islands, and the United States Virgin Islands.
The modern idea of daylight saving was first proposed in 1895 by George Vernon Hudson and it was first implemented by Germany and Austria-Hungary starting on 30 April 1916. Many countries have used it at various times since then. Much of the United States used DST in the 1950s and 1960s, and DST use expanded following the 1970s energy crisis. It has been widely used in North America and Europe since then.
The practice has been both praised and criticized. Although an early goal of DST was to reduce evening use of incandescent lighting (formerly a primary use of electricity), modern heating and cooling usage patterns differ greatly, and research about how DST currently affects energy use is limited or contradictory.
DST clock shifts present other challenges. They complicate timekeeping, and can disrupt meetings, travel, billing, record keeping, medical devices, heavy equipment, and sleep patterns. Software can often adjust computer clocks automatically, but this can be limited and error-prone, particularly when DST dates are changed. History
Although not punctual in the modern sense, ancient civilizations adjusted daily schedules to the sun more flexibly than modern DST does, often dividing daylight into twelve hours regardless of day length, so that each daylight hour was longer during summer. For example, Roman water clocks had different scales for different months of the year: at Rome's latitude the third hour from sunrise, hora tertia, started by modern standards at 09:02 solar time and lasted 44 minutes at the winter solstice, but at the summer solstice it started at 06:58 and lasted 75 minutes. After ancient times, equal-length civil hours eventually supplanted unequal, so civil time no longer varies by season. Unequal hours are still used in a few traditional settings, such as some Mount Athos monasteries and all Jewish ceremonies.
During his time as an American envoy to France, Benjamin Franklin, publisher of the old English proverb, "Early to bed, and early to rise, makes a man healthy, wealthy and wise", anonymously published a letter suggesting that Parisians economize on candles by rising earlier to use morning sunlight. A 1784 satire proposed taxing shutters, rationing candles, and waking the public by ringing church bells and firing cannons at sunrise. Franklin did not propose DST; like ancient Rome, 18th-century Europe did not keep precise schedules. However, this soon changed as rail and communication networks came to require a standardization of time unknown in Franklin's day.
Modern DST was first proposed by the New Zealand entomologist George Vernon Hudson, whose shift-work job gave him leisure time to collect insects, and led him to value after-hours daylight. In 1895 he presented a paper to the Wellington Philosophical Society proposing a two-hour daylight-saving shift, and after considerable interest was expressed in Christchurch, New Zealand, he followed up in an 1898 paper.
Many publications credit DST's proposal to the prominent English builder and outdoorsman William Willett, who independently conceived DST in 1905 during a pre-breakfast ride, when he observed with dismay how many Londoners slept through a large part of a summer's day. An avid golfer, he also disliked cutting short his round at dusk. His solution was to advance the clock during the summer months, a proposal he published two years later. The proposal was taken up by the Liberal Member of Parliament (MP) Robert Pearce, who introduced the first Daylight Saving Bill to the House of Commons on 12 February 1908. A select committee was set up to examine the issue, but Pearce's bill did not become law, and several other bills failed in the following years. Willett lobbied for the proposal in the UK until his death in 1915.
Starting on 30 April 1916, Germany and its World War I allies (Austria-Hungary) were the first to use DST (German: Sommerzeit) as a way to conserve coal during wartime. Britain, most of its allies, and many European neutrals soon followed suit. Russia and a few other countries waited until the next year and the United States adopted it in 1918.
Broadly speaking, Daylight Saving Time was abandoned in the years after the war (with some notable exceptions including Canada, the UK, France, and Ireland for example). However, it was brought back for periods of time in many different places in the coming decades, widely during the Second World War. It became widely adopted, particularly in North America and Europe starting in the 1970s as a result of the 1970s energy crisis.
Since then, the world has seen many enactments, adjustments, and repeals. Procedure
In the case of the United States where a onehour shift occurs at 02:00 local time, in spring the clock jumps forward from the last moment of 01:59 standard time to 03:00 DST and that day has 23 hours, whereas in autumn the clock jumps backward from the last moment of 01:59 DST to 01:00 standard time, repeating that hour, and that day has 25 hours.
Start and end dates vary with location and year. Since 1996 European Summer Time has been observed from the last Sunday in March to the last Sunday in October; previously the rules were not uniform across the European Union. Starting in 2007, most of the United States and Canada observe DST from the second Sunday in March to the first Sunday in November, almost two-thirds of the year. The 2007 US change was part of the Energy Policy Act of 2005; previously, from 1987 through 2006, the start and end dates were the first Sunday in April and the last Sunday in October, and Congress retains the right to go back to the previous dates now that an energyconsumption study has been done.
Beginning and ending dates are roughly the reverse in the southern hemisphere. For example, mainland Chile observes DST from the second Saturday in October to the second Saturday in March, with transitions at 24:00 local time. The time difference between the United Kingdom and mainland Chile may therefore be five hours during the Northern summer, three hours during the Northern winter and four hours a few weeks per year because of mismatch of changing dates.
DST is generally not observed near the equator, where sunrise times do not vary enough to justify it. Some countries observe it only in some regions; for example, southern Brazil observes it while equatorial Brazil does not. Only a minority of the world's population uses DST because Asia and Africa generally do not observe it. Politics
Daylight saving has caused controversy since it began. Winston Churchill argued that it enlarges "the opportunities for the pursuit of health and happiness among the millions of people who live in this country" and pundits have dubbed it "Daylight Slaving Time." Historically, retailing, sports and tourism interests have favored daylight saving, while agricultural and evening entertainment interests have opposed it, and its initial adoption had been prompted by energy crisis and war.
The fate of Willett's 1907 proposal illustrates several political issues involved. The proposal attracted many supporters, including Balfour, Churchill, Lloyd George, MacDonald, Edward VII (who used half-hour DST at Sandringham), the managing director of Harrods, and the manager of the National Bank. However, the opposition was stronger: it included Prime Minister Asquith, Christie (the Astronomer Royal), George Darwin, Napier Shaw (director of the Meteorological Office), many agricultural organizations, and theater owners. After many hearings the proposal was narrowly defeated in a Parliament committee vote in 1909. Willett's allies introduced similar bills every year from 1911 through 1914, to no avail. The US was even more skeptical: Andrew Peters introduced a DST bill to the US House of Representatives in May 1909, but it soon died in committee.
After Germany led the way with starting DST (German: Sommerzeit) during World War I on 30 April 1916 together with its allies to alleviate hardships from wartime coal shortages and air raid blackouts, the political equation changed in other countries; the United Kingdom used DST first on 21 May 1916. US retailing and manufacturing interests led by Pittsburgh industrialist Robert Garland soon began lobbying for DST, but were opposed by railroads. The US's 1917 entry to the war overcame objections, and DST was established in 1918.
The war's end swung the pendulum back. Farmers continued to dislike DST, and many countries repealed it after the war. Britain was an exception: it retained DST nationwide but over the years adjusted transition dates for several reasons, including special rules during the 1920s and 1930s to avoid clock shifts on Easter mornings. The US was more typical: Congress repealed DST after 1919. President Woodrow Wilson, like Willett an avid golfer, vetoed the repeal twice but his second veto was overridden. Only a few US cities retained DST locally thereafter, including New York so that its financial exchanges could maintain an hour of arbitrage trading with London, and Chicago and Cleveland to keep pace with New York. Wilson's successor Warren G. Harding opposed DST as a "deception." Reasoning that people should instead get up and go to work earlier in the summer, he ordered District of Columbia federal employees to start work at 08:00 rather than 09:00 during summer 1922. Some businesses followed suit though many others did not; the experiment was not repeated.
Since Germany's adoption in 1916 the world has seen many enactments, adjustments, and repeals of DST, with similar politics involved. The history of time in the United States includes DST during both world wars, but no standardization of peacetime DST until 1966. In May 1965, for two weeks, St. Paul and Minneapolis were on different times, when the capital city decided to join most of the nation by starting Daylight Saving Time while Minneapolis opted to follow the later date set by state law. In the mid-1980s, Clorox (parent of Kingsford Charcoal) and 7-Eleven provided the primary funding for the Daylight Saving Time Coalition behind the 1987 extension to US DST, and both Idaho senators voted for it based on the premise that during DST fast-food restaurants sell more French fries, which are made from Idaho potatoes. In 1992 after a three-year trial of daylight saving in Queensland, Australia, a referendum on daylight saving was held and defeated with a 54.5% 'no' vote – with regional and rural areas strongly opposed, while those in the metropolitan south-east were in favor. In 2005, the Sporting Goods Manufacturers Association and the National Association of Convenience Stores successfully lobbied for the 2007 extension to US DST.
In December 2008, the Daylight Saving for South East Queensland (DS4SEQ) political party was officially registered in Queensland, advocating the implementation of a dual-time zone arrangement for Daylight Saving in South East Queensland while the rest of the state maintains standard time. DS4SEQ contested the March 2009 Queensland State election with 32 candidates and received one percent of the state-wide primary vote, equating to around 2.5% across the 32 electorates contested. After a three-year trial, more than 55% of Western Australians voted against DST in 2009, with rural areas strongly opposed. On 14 April 2010, after being approached by the DS4SEQ political party, Queensland Independent member Peter Wellington, introduced the Daylight Saving for South East Queensland Referendum Bill 2010 into Queensland Parliament, calling for a referendum to be held at the next State election on the introduction of daylight saving into South East Queensland under a dual-time zone arrangement. The Bill was defeated in Queensland Parliament on 15 June 2011.
In the UK the Royal Society for the Prevention of Accidents supports a proposal to observe SDST's additional hour year-round, but is opposed in some industries, such as postal workers and farmers, and particularly by those living in the northern regions of the UK.
In some Muslim countries DST is temporarily abandoned during Ramadan (the month when no food should be eaten between sunrise and sunset), since the DST would delay the evening dinner. Ramadan took place in July and August in 2012. This concerns at least Morocco and Palestine, although Iran keeps DST during Ramadan. Most Muslim countries do not use DST, partially for this reason.
The 2011 declaration by Russia that it would not turn its clocks back and stay in DST all year long was subsequently followed by a similar declaration from Belarus.
Controversy: Benefits and drawbacks
Proponents of DST generally argue that it saves energy, promotes outdoor leisure activity in the evening, and is therefore good for physical and psychological health, reduces traffic accidents, reduces crime, or is good for business. Groups that tend to support DST are urban workers or professionals, retail businesses, outdoor sports enthusiasts and businesses, tourism operators, and others who benefit from increased light during the evening.
Opponents argue that actual energy savings are inconclusive, that DST can disrupt morning activities, and that the act of changing clocks twice a year is economically and socially disruptive and cancels out any benefit. Groups that have tended to oppose DST are farmers, transportation companies, and the indoor (or darkness reliant) entertainment business.
Retailers, sporting goods makers, and other businesses benefit from extra afternoon sunlight, as it induces customers to shop and to participate in outdoor afternoon sports. In 1984, Fortune magazine estimated that a seven-week extension of DST would yield an additional $30 million for 7-Eleven stores, and the National Golf Foundation estimated the extension would increase golf industry revenues $200 million to $300 million. A 1999 study estimated that DST increases the revenue of the European Union's leisure sector by about 3%.
Conversely, DST can adversely affect farmers and others whose hours are set by the sun and they have traditionally opposed the practice, although farmers are now often neutral or in favor of DST. One reason why farmers used to oppose DST is that grain is best harvested after dew evaporates, so when field hands arrive and leave earlier in summer their labor is less valuable. Dairy farmers are another group who complain of the change as their cows are sensitive to the timing of milking, so when their deliveries need to be made earlier their systems are disrupted. However, their earlier opposition to the practice has been moderated by technological and social changes. Today some farmers groups are even in favour of DST.
DST also hurts prime-time broadcast ratings, drive-ins and other theaters.
Changing clocks and DST rules has a direct economic cost, entailing extra work to support remote meetings, computer applications and the like. For example, a 2007 North American rule change cost an estimated $500 million to $1 billion. Although it has been argued that clock shifts correlate with decreased economic efficiency, and that in 2000 the daylight-saving effect implied an estimated one-day loss of $31 billion on US stock exchanges, the estimated numbers depend on the methodology and the results have been disputed.
Changes to DST rules cause problems in existing computer installations. For example, the 2007 change to DST rules in North America required many computer systems to be upgraded, with the greatest impact on email and calendaring programs; the upgrades consumed a significant effort by corporate information technologists.
Some applications standardize on UTC to avoid problems with clock shifts and time zone differences. Likewise, most modern operating systems internally handle and store all times as UTC and only convert to local time for display.
However, even if UTC is used internally, the systems still require information on time zones to correctly calculate local time where it is needed. Many systems in use today base their date/time calculations from data derived from the IANA time zone database.
In May 1965, for two weeks,
St. Paul and Minneapolis were on different times, when the capital city decided to join most of the nation by starting Daylight Saving Time while Minneapolis opted to follow the later date set by state law. There was no standardization of peacetime
DST in the US until 1966.
In the mid-1980s, Clorox (parent of Kingsford Charcoal) and 7-Eleven provided the primary funding for the
Daylight Saving Time Coalition behind the 1987 extension to US DST, and both Idaho senators voted for it based on the premise that during DST fast-food restaurants sell more
French fries, which are made from Idaho potatoes.
In 1984, Fortune magazine estimated that a seven-week extension of DST would yield an additional $30 million for 7-Eleven stores, and the National Golf Foundation estimated the extension would increase golf industry revenues
$200 million to $300 million.
A 1999 study estimated that DST increases the revenue of the European Union's leisure sector by about 3%.