- Clocks in the US will “fall back” an hour on Sunday, signalling the end of Daylight Saving Time (DST) this year. In Europe, the same happened on October 25.
- With clocks in the US going back an hour, the time difference between New York and India will increase from the current nine and a half hours to ten and a half hours. The time difference with Britain, which was on DST or British Summer Time until October 25, has increased by 1 hour to five and a half hours, as the country is now on Greenwich Mean Time (GMT).
- In the Southern Hemisphere, the opposite has happened, where countries have “sprung forward”, and time difference with India has reduced. Here, clocks have gone ahead by an hour — in New Zealand, the switch this year happened on September 27, and in all states of Australia that have the practice of daylight saving (not all do), on the following Sunday, that is on October 4.
So, what is Daylight Saving Time (DST), and why do clocks in some countries “fall back” and “spring forward”?
- DST is the practice of resetting clocks ahead by an hour in spring, and behind by an hour in autumn (or fall). During these months, countries that follow this system get an extra hour of daylight in the evening.
- Because the spring to fall cycle is opposite in the Northern and Southern Hemispheres, DST lasts from March to October/November in Europe and the US, and from September/October to April in New Zealand and Australia.
- Dates for this switch, which happens twice a year (in the spring and autumn) are decided beforehand. By law, the 28 member states of the European Union switch together — moving forward on the last Sunday of March and falling back on the last Sunday in October. In the US, clocks go back on the first Sunday of November.
How many countries use DST?
- DST is in practice in some 70 countries, including those in the European Union. India does not follow daylight saving time; countries near the Equator do not experience high variations in daytime hours between seasons. (There is, however, a separate debate around the logic of sticking with only one time zone in a country as large as India.)
- In the US, it is practised everywhere except in Hawaii and most of Arizona. In Australia, DST is observed in New South Wales, Victoria, South Australia, and Tasmania besides some other, smaller territories; and not observed in Queensland and Western Australia among other territories.
- Most Muslim countries do not use DST — during the holy month of Ramzan, this could mean delaying the breaking of the fast for longer. Morocco has DST, but suspends it during Ramzan. However, Iran has DST, and stays with it even during Ramzan.
What does this system mean to achieve?
- The rationale behind setting clocks ahead of standard time, usually by 1 hour during springtime, is to ensure that the clocks show a later sunrise and later sunset — in effect a longer evening daytime. Individuals will wake an hour earlier than usual, complete their daily work routines an hour earlier, and have an extra hour of daylight at the end.
- The key argument is that DST is meant to save energy. According to a timeanddate.com report, it was followed by a group of Canadians on July 1, 1908, when residents of Port Arthur, Ontario, turned their clocks forward by an hour. Other locations in Canada soon followed suit. However, the idea did not catch on globally until Germany and Austria introduced DST on April 30, 1916, the rationale being to minimise the use of artificial lighting to save fuel during World War I.
So, has DST achieved its aims?
- A century ago, when DST was introduced, more daylight did mean less use of artificial light. But modern society uses so much energy-consuming appliances all day long that the amount of energy saved is negligible. Various studies have been conducted on the benefits and disadvantages of DST. Among the biggest cons is the disruption of the body clock or circadian rhythm.
- A USA Today report cites a study showing that DST increases the risk of heart attack by 25%, while a return to original times lowers the risk by 21%. It quotes Timothy Morgenthaler, a sleep medicine researcher, as saying that disrupted sleep patterns might affect memory, learning, social interactions and overall cognitive performance.
- An article in Popular Science cites studies to list out the disadvantages of DST. One hour of lost sleep in the US, one study calculated, increases the fatal crash rate by 5.4% to 7.6% for six days following the transition.
- Other studies found a higher rate of workplace injuries after the switch, leading to lost days of work; a slight drop in stock market performance; health problems as a result of disruption of the circadian rhythm (body clock) — and even longer sentences ordered by judges deprived of sleep.
Countries that want DST gone
- In March last year, the European Union moved to scrap the custom of DST, with the European Parliament voting 410-192. After 2021, EU member states will choose between “permanent summertime” or “permanent wintertime”. Those who choose the former will reset their clocks for the last time in March 2021; those who choose the latter would do so in October 2021.
- In the US too, the changing of clocks is the subject of a debate that recurs every year, and a large number of people protest against the “torture”.