Rationale and original idea of Daylight Saving Time

[Woodmonkey]

Rationale and original idea

The main purpose of Daylight Saving Time (called "Summer Time" in many places in the world) is to make better use of daylight. We change our clocks during the summer months to move an hour of daylight from the morning to the evening. Countries have different change dates. Glide your cursor over the map to see how changing the clocks affects different latitudes.

If you live near the equator, day and night are nearly the same length (12 hours). But elsewhere on Earth, there is much more daylight in the summer than in the winter. The closer you live to the North or South Pole, the longer the period of daylight in the summer. Thus, Daylight Saving Time (Summer Time) is usually not helpful in the tropics, and countries near the equator generally do not change their clocks.

A poll conducted by the U.S. Department of Transportation indicated that Americans liked Daylight Saving Time because "there is more light in the evenings / can do more in the evenings." A 1976 survey of 2.7 million citizens in New South Wales, Australia, found 68% liked daylight saving. Indeed, some say that the primary reason that Daylight Saving Time is a part of many societies is simply because people like to enjoy long summer evenings, and that reasons such as energy conservation are merely rationalizations.
However, Daylight Saving Time does save energy. Studies done by the U.S. Department of Transportation show that Daylight Saving Time trims the entire country's electricity usage by a small but significant amount, about one percent each day, because less electricity is used for lighting and appliances. Similarly, in New Zealand, power companies have found that power usage decreases 3.5 percent when daylight saving starts. In the first week, peak evening consumption commonly drops around five percent.

Energy use and the demand for electricity for lighting homes is directly related to the times when people go to bed at night and rise in the morning. In the average home, 25 percent of electricity is used for lighting and small appliances, such as TVs, VCRs, and stereos. A good percentage of energy consumed by lighting and appliances occurs in the evening when families are home. By moving the clock ahead one hour, the amount of electricity consumed each day decreases.

In the summer, people who rise before the sun rises use more energy in the morning than if DST was not in effect. However, although 70 percent of Americans rise before 7:00 a.m., this waste of energy from having less sunlight in the morning is more than offset by the savings of energy that results from more sunlight in the evening.

In the winter, the afternoon Daylight Saving Time advantage is offset for many people and businesses by the morning's need for more lighting. In spring and fall, the advantage is generally less than one hour. So, Daylight Saving Time saves energy for lighting in all seasons of the year, but it saves least during the four darkest months of winter (November, December, January, and February), when the afternoon advantage is offset by the need for lighting because of late sunrise.

In addition, less electricity is used because people are home fewer hours during the "longer" days of spring and summer. Most people plan outdoor activities in the extra daylight hours. When people are not at home, they don't turn on the appliances and lights.

There is a public health benefit to Daylight Saving Time, as it decreases traffic accidents. Several studies in the U.S. and Great Britain have found that the DST daylight shift reduces net traffic accidents and fatalities by close to one percent. An increase in accidents in the dark mornings is more than offset by the evening decrease in accidents.

Opposition to Daylight Saving

Many people intensely dislike Daylight Saving Time. Frequent complaints are the inconvenience of changing many clocks and adjusting to a new sleep schedule. For most people, this is a mere nuisance, but some people with sleep disorders find this transition very difficult. Indeed, there is evidence that the severity of auto accidents increases and work productivity decreases as people adjust to the time change.

Some argue that the energy savings touted by DST is offset by the energy used by those living in warm climates to cool their homes during summer afternoons and evenings. Similarly, the argument can be made that more evening hours of light encourage people to run errands and visit friends, thus consuming more gasoline.

Protests are also put forth by people who wake at dawn, or whose schedules are otherwise tied to sunrise, such as farmers. Canadian poultry producer Marty Notenbomer notes, "The chickens do not adapt to the changed clock until several weeks have gone by, so the first week of April and the last week of October are very frustrating for us."

In Israel, ultra-Orthodox Sephardic Jews have campaigned against Daylight Saving Time because they recite Slikhot penitential prayers in the early morning hours during the Jewish month of Elul.

A writer in 1947 noted, "I don't really care how time is reckoned so long as there is some agreement about it, but I object to being told that I am saving daylight when my reason tells me that I am doing nothing of the kind. I even object to the implication that I am wasting something valuable if I stay in bed after the sun has risen. As an admirer of moonlight I resent the bossy insistence of those who want to reduce my time for enjoying it. At the back of the Daylight Saving scheme I detect the bony, blue-fingered hand of Puritanism, eager to push people into bed earlier, and get them up earlier, to make them healthy, wealthy and wise in spite of themselves." (Robertson Davies, The Diary of Samuel Marchbanks, 1947, XIX, Sunday.)

Sometimes people recommend a "compromise," wherein clocks would be set one-half hour forward year round. While this may initially sound appealing, it is not a good solution. In the winter months, when daylight saving is not occurring, our clock is divided such that noon should be the middle of the day (although since time zones are so wide, this does not always happen). In the summer, when there are more daylight hours, we want to shift a full hour to the evening.

Some countries set their clocks to fractional time zones. For example, Kathmandu, Nepal is 5:45 hours ahead of Universal Time, and Calcutta (Kolkatta), India is 5:30 ahead. This is not an attempt to compromise and have half Daylight Saving Time year-round, but rather an adjustment made because the countries straddle international time zones.

Idea of Daylight Saving Time

The idea of daylight saving was first conceived by Benjamin Franklin (portrait at right) during his sojourn as an American delegate in Paris in 1784, in an essay, "An Economical Project." Read more about Franklin's essay.

Some of Franklin's friends, inventors of a new kind of oil lamp, were so taken by the scheme that they continued corresponding with Franklin even after he returned to America.

The idea was first advocated seriously by London builder William Willett (1857-1915) in the pamphlet, "Waste of Daylight" (1907), that proposed advancing clocks 20 minutes on each of four Sundays in April, and retarding them by the same amount on four Sundays in September. As he was taking an early morning a ride through Petts Wood, near Croydon, Willett was struck by the fact that the blinds of nearby houses were closed, even though the sun was fully risen. When questioned as to why he didn't simply get up an hour earlier, Willett replied with typical British humor, "What?" In his pamphlet "The Waste of Daylight" he wrote:

"Everyone appreciates the long, light evenings. Everyone laments their shortage as Autumn approaches; and everyone has given utterance to regret that the clear, bright light of an early morning during Spring and Summer months is so seldom seen or used."

Early British laws and lax observance

About one year after Willett began to advocate daylight saving (he spent a fortune lobbying), he attracted the attention of the authorities. Robert Pearce - later Sir Robert Pearce - introduced a bill in the House of Commons to make it compulsory to adjust the clocks. The bill was drafted in 1909 and introduced in Parliament several times, but it met with ridicule and opposition, especially from farming interests. Generally lampooned at the time, Willett died on March 4, 1915.

Following Germany’s lead, Britain passed an act on May 17, 1916, and Willett’s scheme of adding 80 minutes, in four separate movements was put in operation on the following Sunday, May 21, 1916. There was a storm of opposition, confusion, and prejudice. The Royal Meteorological Society insisted that Greenwich time would still be used to measure tides. The parks belonging to the Office of Works and the London County Council decided to close at dusk, which meant that they would be open an extra hour in the evening. Kew Gardens, on the other hand, ignored the daylight saving scheme and decided to close by the clock.

In Edinburgh, the confusion was even more marked, for the gun at the Castle was fired at 1:00 p.m. Summer Time, while the ball on the top of the Nelson monument on Calton Hill fell at 1:00 Greenwich Time. That arrangement was carried on for the benefit of seamen who could see it from the Firth of Forth. The time fixed for changing clocks was 2:00 a.m. on a Sunday.
There was a fair bit of opposition from the general public and from agricultural interests who wanted daylight in the morning, but Lord Balfour came forward with a unique concern:

"Supposing some unfortunate lady was confined with twins and one child was born 10 minutes before 1 o'clock. ... the time of birth of the two children would be reversed. ... Such an alteration might conceivably affect the property and titles in that House."

After World War I, Parliament passed several acts relating to Summer Time. In 1925, a law was enacted that Summer Time should begin on the day following the third Saturday in April (or one week earlier if that day was Easter Day). The date for closing of Summer Time was fixed for the day after the first Saturday in October.

The energy saving benefits of Summer Time were recognized during World War II, when clocks in Britain were put two hours ahead of GMT during the summer. This became known as Double Summer Time. During the war, clocks remained one hour ahead of GMT throughout the winter.

First there was standard time

For millennia, people have measured time based on the position of the sun; it was noon when the sun was highest in the sky. Sundials were used well into the Middle Ages, at which time mechanical clocks began to appear. Cities would set their town clock by measuring the position of the sun, but every city would be on a slightly different time.

The time indicated by the apparent sun on a sundial is called Apparent Solar Time, or true local time. The time shown by the fictitious sun is called Mean Solar Time, or local mean time when measured in terms of any longitudinal meridian.

Standard time begins in Britain

Britain was the first country to set the time throughout a region to one standard time. The railways cared most about the inconsistencies of local mean time, and they forced a uniform time on the country. The original idea was credited to Dr. William Hyde Wollaston (1766-1828) and was popularized by Abraham Follett Osler (1808-1903). The Great Western Railway was the first to adopt London time, in November 1840. Other railways followed suit, and by 1847 most (though not all) railways used London time. On September 22, 1847, the Railway Clearing House, an industry standards body, recommended that GMT be adopted at all stations as soon as the General Post Office permitted it. The transition occurred on December 1 for the L&NW, the Caledonian, and presumably other railways; the January 1848 Bradshaw's lists many railways as using GMT. By 1855, the vast majority of public clocks in Britain were set to GMT (though some, like the great clock on Tom Tower at Christ Church, Oxford, were fitted with two minute hands, one for local time and one for GMT). The last major holdout was the legal system, which stubbornly stuck to local time for many years, leading to oddities like polls opening at 08:13 and closing at 16:13. The legal system finally switched to GMT when the Statutes (Definition of Time) Act took effect; it received the Royal Assent on August 2, 1880.

Standard time in the US

Standard time in time zones was instituted in the U.S. and Canada by the railroads on November 18, 1883. Prior to that, time of day was a local matter, and most cities and towns used some form of local solar time, maintained by a well-known clock (on a church steeple, for example, or in a jeweler's window). The new standard time system was not immediately embraced by all, however. (The train at right is a Union locomotive used during the American Civil War, photo ca. 1861-1865.)

The first man in the United States to sense the growing need for time standardization was an amateur astronomer, William Lambert, who as early as 1809 presented to Congress a recommendation for the establishment of time meridians. This was not adopted, nor was the initial suggestion of Charles Dowd of Saratoga Springs, N.Y., in 1870. Dowd revised his proposal in 1872, and it was adopted virtually unchanged by U.S. and Canadian railways eleven years later.

Detroit kept local time until 1900, when the City Council decreed that clocks should be put back 28 minutes to Central Standard Time. Half the city obeyed, while half refused. After considerable debate, the decision was rescinded and the city reverted to sun time. A derisive offer to erect a sundial in front of the city hall was referred to the Committee on Sewers. Then, in 1905, Central Standard Time was adopted by city vote.

It remained for a Canadian civil and railway engineer, Sandford Fleming, to instigate the initial effort that led to the adoption of the present time meridians in both Canada and the U.S. Time zones were first used by the railroads in 1883 to standardize their schedules. Canada's Sir Sandford Fleming (posing at left, at the driving the last spike of the Canadian Pacific Railway. Sandford Fleming wears the stovepipe hat and is to the left of the man with the hammer) also played a key role in the development of a worldwide system of keeping time. Trains had made the old system - where major cities and regions set clocks according to local astronomical conditions - obsolete. Fleming advocated the adoption of a standard or mean time and hourly variations from that according to established time zones. He was instrumental in convening the 1884 International Prime Meridian Conference in Washington, at which the system of international standard time - still in use today - was adopted.

Although the large railway systems in U.S. and Canada adopted standard time at noon on November 18, 1883, it was many years before such time was actually used by the people themselves.

The use of standard time gradually increased because of its obvious practical advantages for communication and travel. Standard time in time zones was established by U.S. law with the Standard Time Act of 1918, enacted on March 19. Congress adopted standard time zones based on those set up by the railroads, and gave the responsibility to make any changes in the time zones to the Interstate Commerce Commission, the only federal transportation regulatory agency at the time. When Congress created the Department of Transportation in 1966, it transferred the responsibility for the time laws to the new department.

Time zone boundaries have changed greatly since their original introduction and changes still occasionally occur. The Department of Transportation conducts rulemakings to consider requests for changes. Generally, time zone boundaries have tended to shift westward. Places on the eastern edge of a time zone can effectively move sunset an hour later (by the clock) by shifting to the time zone immediately to their east. If they do so, the boundary of that zone is locally shifted to the west; the accumulation of such changes results in the long-term westward trend. The process is not inexorable, however, since the late sunrises experienced by such places during the winter may be regarded as too undesirable. Furthermore, under the law, the principal standard for deciding on a time zone change is the "convenience of commerce." Proposed time zone changes have been both approved and rejected based on this criterion, although most such proposals have been accepted.

Early adoption in law

Daylight Saving Time has been used in the U.S. and in many European countries since World War I. At that time, in an effort to conserve fuel needed to produce electric power, Germany and Austria took time by the forelock, and began saving daylight at 11:00 p.m. on April 30, 1916, by advancing the hands of the clock one hour until the following October. Other countries immediately adopted this 1916 action: Belgium, Denmark, France, Italy, Luxembourg, Netherlands, Norway, Portugal, Sweden, Turkey, and Tasmania. Nova Scotia and Manitoba adopted it as well, with Britain following suit three weeks later, on May 21, 1916. In 1917, Australia and Newfoundland began saving daylight.

The plan was not formally adopted in the U.S. until 1918. 'An Act to preserve daylight and provide standard time for the United States' was enacted on March 19, 1918. [See law] It both established standard time zones and set summer DST to begin on March 31, 1918. Daylight Saving Time was observed for seven months in 1918 and 1919. After the War ended, the law proved so unpopular (mostly because people rose earlier and went to bed earlier than people do today) that it was repealed in 1919 with a Congressional override of President Wilson's veto. Daylight Saving Time became a local option, and was continued in a few states, such as Massachusetts and Rhode Island, and in some cities, such as New York, Philadelphia, and Chicago.

During World War II, President Franklin Roosevelt instituted year-round Daylight Saving Time, called “War Time,” from February 2, 1942 to September 30, 1945. [See law] From 1945 to 1966, there was no federal law regarding Daylight Saving Time, so states and localities were free to choose whether or not to observe Daylight Saving Time and could choose when it began and ended. This understandably caused confusion, especially for the broadcasting industry, as well as for railways, airlines, and bus companies. Because of the different local customs and laws, radio and TV stations and the transportation companies had to publish new schedules every time a state or town began or ended Daylight Saving Time.

On January 4, 1974, President Nixon signed into law the Emergency Daylight Saving Time Energy Conservation Act of 1973. Then, beginning on January 6, 1974, implementing the Daylight Saving Time Energy Act, clocks were set ahead for a 15-month period through April 27, 1975.

Inconsistent use in the U.S.

In the early 1960s, observance of Daylight Saving Time was quite inconsistent, with a hodgepodge of time observances, and no agreement about when to change clocks. The Interstate Commerce Commission, the nation's timekeeper, was immobilized, and the matter remained deadlocked. Many business interests were supportive of standardization, although it became a bitter fight between the indoor and outdoor theater industries. The farmers, however, were opposed to such uniformity. State and local governments were a mixed bag, depending on local conditions.

Efforts at standardization were encouraged by a transportation industry organization, the Committee for Time Uniformity. They surveyed the entire nation, through questioning telephone operators as to local time observances, and found the situation was quite confusing. Next, the Committee's goal was a strong supportive story on the front page of the New York Times. Having rallied the general public's support, the Time Uniformity Committee's goal was accomplished, but only after discovering and disclosing that on the 35-mile stretch of highway (Route 2) between Moundsville, W.V., and Steubenville, Ohio, every bus driver and his passengers had to endure seven time changes!

The Uniform Time Act

By 1966, some 100 million Americans were observing Daylight Saving Time based on their local laws and customs. Congress decided to step in and end the confusion, and to establish one pattern across the country. The Uniform Time Act of 1966 (15 U.S. Code Section 260a) [see law], signed into Public Law 89-387 on April 12, 1966, by President Lyndon Johnson, created Daylight Saving Time to begin on the last Sunday of April and to end on the last Sunday of October. Any State that wanted to be exempt from Daylight Saving Time could do so by passing a state law.

The Uniform Time Act of 1966 established a system of uniform (within each time zone) Daylight Saving Time throughout the U.S. and its possessions, exempting only those states in which the legislatures voted to keep the entire state on standard time.

In 1972, Congress revised the law to provide that, if a state was in two or more time zones, the state could exempt the part of the state that was in one time zone while providing that the part of the state in a different time zone would observe Daylight Saving Time. The Federal law was amended in 1986 to begin Daylight Saving Time on the first Sunday in April.

Under legislation enacted in 1986, Daylight Saving Time in the U.S. began at 2:00 a.m. on the first Sunday of April and ended at 2:00 a.m. on the last Sunday of October.

The Energy Policy Act of 2005 extended Daylight Saving Time in the U.S. beginning in 2007, though Congress retained the right to revert to the 1986 law should the change prove unpopular or if energy savings are not significant. Going from 2007 forward, Daylight Saving Time in the U.S.

* begins at 2:00 a.m. on the second Sunday of March and
* ends at 2:00 a.m. on the first Sunday of November

In most of the countries of Western Europe, including the countries that are members of the EU, Daylight Saving Time:

* begins at 1:00 a.m. GMT on the last Sunday of March and
* ends at 1:00 a.m. GMT on the last Sunday of October

Observance of Daylight Saving Time elsewhere in the world is highly variable. See Worldwide daylight saving.



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