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Daylight Saving Time – DST – Summer Time

Daylight Saving Time (DST) is the practice of setting the clocks forward one hour from standard time during the summer months, and back again in the fall, in order to make better use of natural daylight.

Commuters and tourists in Canary Wharf, London, United Kingdom.

The sculpture "Six Public Clocks" in London.

Commuters and tourists walking through the sculpture Six Public Clocks by Konstantin Grcic in 1999 in Canary Wharf, London, U.K.

©iStockphoto.com/william87

Clocks Back or Forward?

“Spring forward, fall back” is one of the little sayings used to remember which way to set your watch. You set your clock forward one hour in the spring when DST starts (= lose 1 hour), and back one hour when DST ends in the fall (= regain 1 hour).

Northern Hemisphere

North America, Central America, Europe, Asia, northern Africa

Many countries in the Northern Hemisphere (north of the equator) use DST in the summer time, but not all. Daylight Saving Time usually starts in March-April and ends in September-November when the countries return to standard time.

Southern Hemisphere

Australia, New Zealand, most of South America, southern Africa

In the Southern Hemisphere (south of the equator) the participating countries usually start the DST period in September-November and end DST in March-April.

Not without Controversy

In the US, proposals to abolish the yearly time change regularly appear on the legislative agenda.

In November 2018, California voters approved “Proposition 7”, allowing for the possibility to put Californians on year-round DST. In Florida, a bill dubbed the “Sunshine Protection Act” was passed on to Congress in March 2018, eliminating the practice of setting the clocks twice a year. The Bill is awaiting approval at the federal level.

From experience, similar efforts to end DST have previously been voted down in the legislative system before they reach Congress.

EU Pushing to Scrap DST

In 2018, the European Commission issued a draft directive to scrap DST in the European Union (EU) permanently.

In a public survey, more than 80% of 4.6 million respondents voted to put an end to seasonal clock changes altogether, but several EU Member States have called for more time before putting an end to the practice.

More Than 100 Years

When Germany first set the clocks forward on April 30, 1916, it became the first country in the world to use DST on a national level. However, the town of Thunder Bay in Ontario, Canada implemented DST as far back as 1908.

Suggested Earlier

US inventor and politician Benjamin Franklin first proposed the concept of DST in 1784, but modern Daylight Saving Time was first suggested in 1895. At that time, George Vernon Hudson, an entomologist from New Zealand, presented a proposal for a 2-hour daylight saving shift.

Why Use DST at All?

Less than 40% of the countries in the world use DST. Some countries use it to make better use of the natural daylight in the evenings. The difference in light is most noticeable in the areas at a certain distance from Earth's equator.

Some studies show that DST could lead to fewer road accidents and injuries by supplying more daylight during the hours more people use the roads. Other studies claim that people's health might suffer due to DST changes.

DST is also used to reduce the amount of energy needed for artificial lighting during the evening hours. However, many studies disagree about DST's energy savings, and while some studies show a positive outcome, others do not.

Not Always One Hour

Today clocks are almost always set one hour back or ahead.

However, on Lord Howe Island, Australia, clocks are set only 30 minutes forward from LHST (UTC+10:30) to LHDT (UTC+11) during DST.

Throughout history, there have been several variations, like half adjustments (30 minutes) or double adjustment (2 hours). Adjustments of 20 and 40 minutes have also been used.

Topics: Daylight Saving Time, Timekeeping

DST in Boston, USA

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Daylight Saving Time – DST

  1. One Hour Back or Forward?
  2. What Is Standard Time?
  3. Savings or Saving?
  4. Pros and Cons of DST
  5. Your Health and DST
  6. Summer or Winter Time?
  7. History of DST
  8. DST in the USA
  9. History of DST in Europe
  10. How Does DST Work?
  11. DST Statistics

Time Zones & DST


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