The summer-time is a mode used by a great number of countries consisting in adjusting the official Local time, generally of an hour compared to the Time zone standard for the periods of the Printemps, the be and the beginning of the Automne.

The interest of the summer-time resides, according to its promoters, in energy saving which it is supposed to allow, on the basis of use better of natural solar light for the summer period; this approach is however rejected by its detractors.

This measurement is mainly used in the moderate areas , where the seasonal variations of luminosity make measurement relevant.

For the Europe (except Iceland) the period extends by decree from last Sunday from March at last Sunday from October. Each country is free to choose like Heure of winter one hour fixed on the meridian line of its time zone like the Great Britain or the Portugal or to shift it one hour like the France.

For the North America, and starting from 2007, this summer period begins in the night from second Sunday from March, while the return to the normal hour is made first Sunday of November. (Note of the month of October 2006: after the adoption of the “ ”, as from 2007, the the United States and Canada rock between the summer-time and the hours of winter in the following way: the passage to the summer-time is made second Sunday of March whereas the return is made first Sunday of November. One will have to expect that other countries change also their dates of passage to align itself on North America.)

At the time of the passage to the summer-time, at one hour in universal Time coordinated, that is to say at two o'clock in the morning in European hour of winter (one hour in Great Britain and in Portugal, three hours in Eastern Europe), the watches are advanced sixty minutes, so that it is usually known as that “one hour of sleep is lost”. At the time of the passage to the Hour of winter, at one hour in universal time, that is to say at three o'clock in the morning in European hour of summer (two hours in Great Britain and in Portugal, four hours in Eastern Europe), the watches are delayed sixty minutes, and “an hour of sleep is gained”.

History

In April 1784, Benjamin Franklin evokes for the first time in the French daily newspaper the Newspaper of Paris the possibility of shifting the schedules in order to save energy. The idea remains however without continuation and only starting from 1907 by the British William Willet is taken again who starts a campaign against “the wasting of the light”. Germany is the first to found this change of hour on April 30th, 1916 and quickly is followed by English on May 21st, 1916: the Parliament sets up the British Standard Time , in one hour advance immediately of the meridian line of Greenwich. The idea is taken up by the Ireland and the Italy, like by the majority of the European countries after the war. In Germany, between 1947 and 1949, one founds even a Hochsommerzeit where the watches were shifted of a second hour between the May 11th and the June 29th.

In France, the hour of summer was proposed by the low-alpine deputy André Honnorat then instituted in June 1916 (law voted in April 1916) and given up in 1946 with a certain confusion between zone free and occupied during the Occupation (the occupied zone being at the German hour). It is the March 28th 1976, following the oil crisis of 1973, which one restored the summer-time: the objective was to carry out savings in energy by reducing the needs for lighting in evening.

The estival change of hour was introduced into the worldwide of the European Union at the beginning of the Années 1980. To facilitate transport, the communications and the exchanges within the EU, it was decided to harmonize the dates of change of hour in 1998, by the directive 2000/84/CE of the the European Parliament and the Conseil.

Summer-time in the world

Because of the weak variation of the diurnal duration in the areas close to the equator, the tropical countries generally do not have recourse to the change of hour.

Northern hemisphere

The countries of the northern Hemisphere which have recourse to the change of hour, in particular the the United States (as in the State of California), the Canada except the province of Saskatchewan and the European countries except the Iceland, do it on close dates.

With the Morocco, a system of summer-time similar to that of France east in project. The Moroccan State evokes many advantages with this project, on various scales: as well on the level energy saving as on the plan tourism.

  • the following countries and areas observe the summer-time starting from the first Sunday of the month of April, at 2 o'clock in the morning, until the last Sunday of October:

  • Canada and the United States followed until 2006 the schedule of preceding change. Following the adoption of the Energy Policy Act of 2005 by the United States, the passage to the summer-time takes place second Sunday of March, at 2 o'clock in the morning, and the return per hour of winter takes place first Sunday of November. Canada adopted the same dates in order to harmonize the economic exchanges between the countries); that makes it possible to advance three weeks the passage to the summer-time. The experts estimate that this decision could involve an energy saving of 4,4 billion dollars from here at 2020.

    • Canada, except:
      • the part is Colombia-British
      • the Saskatchewan (the part of the agglomeration of Lloydminster being in this province applies the summer-time however, as in the close Alberta)
      • the island of Southampton to the Nunavut
      • the areas of Atikokan, New Osnaburgh and Pickle Lake in the Ontario
    • the United States, except:
      • the Arizona. The Nation Navajo respects it however but the reserve Hopi, wedged inside this one, does not respect it.
      • majority of the counties of the Indiana before April 2006.
      • external territories

Southern hemisphere

The change of hour also takes place in certain countries of the Southern hemisphere, but on different dates, so that the jet lag between country can take three different values according to the moment in the year. For example, the shift between the Chile and France are worth six hours in full boreal summer, four hours in full boreal winter, but can be worth five hours at the periods close to the dates of change of hour.

  • Chile, of first Sunday after the October 9th with 4:00 until first Sunday after the March 9th with 3:00.

  • Falkland Islands, of first Sunday of September until third Sunday of April to 2:00.
  • Namibia, of first Sunday of September at first Sunday of April, with 2:00.
  • New Zealand, of first Sunday of October at third Sunday of March, with 2:00.
  • Paraguay, of third Sunday of October at second Sunday of March, at midnight.
  • Uruguay, according to fixed dates each year (of the September 25th to the March 26th for the period 2005 - 2006)

Summer-time in France

Interest of the introduction of a summer time

Which are concretely the advantages of the introduction of a summer time? When it grows dark, the needs for lighting are numerous, and many consumption of electricity also consequently. Since the end of the second world war until 1973, the hour of winter was perpetual. Following the oil crisis, savings in electricity were perceived like really necessary. One then founded the summer-time. Why?

The objective is to reduce consumption of electricity as regards lighting in evening. However, the interest is real as from spring. Indeed, at March 31st for example, in Paris region, the day rises, hour of winter, towards 6:00, and the night fall towards 19:45. While shifting the one hour schedule ahead, one arrives at the fact that the day rises towards 7:00, and the night fall towards 20:45. Thus the night is shifted one hour about the morning. However consumption of electricity to light is quite less between 6:00 and 7:00 the morning, which between 19:45 and 20:45 the evening. From where interest of the passage to the summer-time for energy saving.

And while approaching the summer, the sun will rise more and more early with the prolongation of the days until June, summer solstice. What reduces consumption of electricity to light the morning, and still much more the evening. For illustrating well, let us examine the case of June 21st, one of the longest days of the year. If the hour of winter were applied all the year, the day would rise towards 4:15 of the morning, and the night would fall towards 21:30. With the summer-time, the day lasts of 5:15 to 22:30 approximately. And it is obvious that consumption of electricity between 21:30 and 22:30 is much more important than between 4:15 and 5:15 of the morning. At the time of the summer solstice, certain people conceive besides without problem, thanks to the summer time, not to use any lighting, lying down sufficiently early to live perpetually of day during the season. The summer time appears, for this case, even more interesting, from the point of view of savings in electricity, that for March.

From July, the days are seen starting to decrease. And towards the end of September, they are shortened considerably. Consumption of electricity to light the morning multiplies then, as to raise it day becomes increasingly late.

In winter, the days of short duration return a great consumption of inevitable electricity. In the measurement or, during the week, the majority of the people wake up before the rising of the day and fall asleep after fallen the night, a change of schedule would not be very obviously useful. Why not found the summer-time all the year, to delay one hour the moment when consumption of electricity starts in evening? Quite simply, because around the January 1st, the day rises, hour of winter, towards 8:15; and that the summer-time in application at this time there of the year would have as a consequence to still raise it day an hour later, that is to say towards 9:15. Admittedly, fallen the night, actually towards 17:30 would pass to 18:30; but to rise and leave to work under one night complete being a psychological disturbance for many people, whereas to return at home and to dine on night is more usual and less disturbing for the moral one, to privilege the day the morning are more important than the evening. From where the maintenance of the hour of winter for five months of the year. A change of hour during this season would not have any really provable utility.

Energy profit

In France, a study carried out jointly by the ministry for Industry, EDF and the Agency of the environment and the control of energy (ADEME) estimated that in 1996 the saving in electricity (station of lighting) was approximately 1,3 T Wh (either approximately: 293000 Mtoe in equivalence primary energy). Always according to the ADEME, the post office of electricity consumption in lighting slightly evolved/moved these last years and the energy saved in 2003 would be always of 1,3 Twh, that is to say 0,28% of the domestic consumption of electricity and 4% of the total consumption of lighting.

Dispute of the change of hour

The change of hour is discussed for many reasons:
  • the hour does not correspond any more to the natural solar rate/rhythm since, in certain Western zones of Europe (France - in Brest, the shift is 2:18 - and Spain), it is “midday (solar) at fourteen hours (legal)” in summer.
  • the period subjected to the hard summer-time in fact more than 7 months, and thus includes/understands almost the totality of spring, and more than one month in autumn: the durations on both sides of the summer solstice are not symmetrical any more. So the majority of the people held with daily obligations must rise before the rising of the day for enough a long period; this can involve psychological problems, in particular in the children. This dissymmetry was founded for psychiatric reasons: indeed, the period of the autumnal equinox corresponds to the fastest fall of the duration of the day; compound with the passage per hour of winter, that can involve depressions, even Suicide S at the sensitive people.
  • the two annual changes of hour are shown to disturb the rate/rhythm of the Biological clock, in particular in the children (who lose one hour of sleep at the time of the passage to the summer-time) and the pets: the change of hour of the draft of the milch cows disturbs them deeply and it always follows a production decrease of milk and especially of the stress of which it is largely shown that it deteriorates the quality of milk.
  • Of very many recording and display systems of the hour does not make it possible to differentiate two events spaced from exactly an hour, this concerning single a 2 hours period per annum (1 year = 8760 H), that is to say 0,023% of time; on this occasion, the accident risks in dangerous installations (refinery, chemical plant, etc) are increased, because possible confusion in the chronology of the events increases the probability of a human failure.
  • While placing the peak periods of traffic motor vehicle for the hottest period of the summer, the Pollution atmospheric due to the cars is increased.
  • the fall of consumption of lighting could be compensated by the increase in the needs for heating the morning at the beginning of spring - a report/ratio of the School of the mines of 1992 concluded however for a tiny purpose (< 0,1 TWh for France). So on a side one observes a broader diffusion of the lamps with energy saving since 2000 (fluocompactes), which contradicts the argument “savings in lighting”, on the other hand, modern leisures take place mainly the evening and are large consumers of electricity, that it is dawning or that it grows dark: the home-cinema, the giant flat panel displays, the vidéoprojecteurs, video game consoles, computers (the more so as the massive arrival of the ADSL encourages to leave the computers lit longer).
  • the change of hour costs much money, time and energy: personnel employed to manually put per hour the mechanical public clocks, the SNCF and the airline companies which must envisage special schedules for this night.

Data processing

The standard ISO concerning the date allows a computerized treatment of the hour and estival change of hour. The Character string representing the hour indicates the Time zone accompanied by the possible change of hour: for example, the Standard time French is noted in winter THIS ( Central European time , Central Europe time) and in summer CEST ( Central European summer time , summer-time of Central Europe).

To avoid the misunderstandings and of possible data-processing bugs, the conveyers avoid programming departures between 2 and 3 hours of the morning at the time of the return per hour of winter: because of the one hour shift, it is twice 2 hours of the morning.

European Union

As from the year the 2002 change of summer-time and in winter must be done on preset dates (directive 2000/84/CE of the the European Parliament and council):
  • the period of the summer-time starts, to 1 hour of the morning, universal time , last Sunday of March;
  • the period of the summer-time finishes, to 1 hour of the morning, universal time , last Sunday of October;
If the date is standardized and imposed, each country is free to pass or not in summer-time. On the other hand each one must announce its choice at least five years in advance.

See too

Internal bonds

External bonds

Three sites presenting inter alia information immediately summer of all the countries of the world:
  • '' Time and Date.com ''
  • '' Complete time zone information for all countries ''
  • '' Greenwich Mean Time ''

A site showing the benefit of the change of hour:

  • Pourquoi does one change hour?

References

Random links:Roger Estrange | Code of Vava' U | Eagle To rivet (Michigan) | Hairspray (original soundtrack) | Abd Al-Malik Al-Muzaffar

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