12 December 2011

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History What is DST daylight saving time Understanding DST or Summer Time? DST gift of World War

History What is DST daylight saving time Understanding DST or Summer Time?
DST gift of World War

Daylight Saving Time, or DST, is the period of the year when clocks are moved one hour ahead.

DST = Better use of the evening daylight

DST does not add daylight but it gives more usable hours of daylight.

Few countries observe the DST Timing and few countries do not observe DST.

Countries use the DST to save time or say they want to utilize the time proper way as once time the moment is gone its gone forever.

DST stands for Daylight Saving Time

Daylight saving time is abbreviated as “DST”,

DST that is Daylight saving time is called as Summer Time or daylight savings.

So exactly what is the DST?

Daylight saving time (DST) is a change in the standard time.

Daylight Saving Time (DST) system, clocks are adjusted forward one hour near the start of spring and are adjusted backward in the fall.

When spring starts clocks are adjusted forward one hour.
In autumn again clocks are adjusted backward.

In other words we can say that Daylight Saving Time (DST) is the practice of turning the clock ahead as warmer weather approaches and back as it becomes colder again.

DST is the practice of temporarily advancing clocks during the summertime so that afternoons have more daylight and mornings have less.

DST is the method by which we get the more light out of the day by forwarding clocks by one hour during the summer.

During this time Sun appears to rise one hour later in the morning and sets one hour later in the evening which gives the feeling that day has become longer.

Daylight saving time begins in the northern hemisphere between March–April and ends between September–November.

Daylight saving time begins in the southern hemisphere between September–November and ends between March–April.

But what happens exactly – what happens to clock
When DST starts in spring we lose one hour, the clock moves forward.

In a typical case where a one-hour 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

When DST ends in FALL time falls back one hour thus we get one hour which we lost when the spring started.

DST and terms Spring Forward and FALL Back
The term “to spring forward” refers to when people set the clocks one hour forward, marking the start of DST
The term “to fall back” suggests that one must set the clocks one hour back when DST ends.

What is the reason to adjust the time this way?

The extra hour of daylight in the evening gives everyone more time for example school children can play and older people can walk or arrange parties or plan travel.
Its gives opportunity to spend more time increases the social gathering time.

DST also helps to save the electricity.

Clocks are set one hour ahead during the spring, and one hour back to standard time in the autumn.

But reality is people do not bother to save electricity or artificial light in after noon also.
Without shutting the AC or Fan or Lights people go outside of the homes and offices.

Short History of DST Day light saving time

Germany was one of the first countries to observe DST.

In 1784 Benjamin Franklin first suggested Daylight Saving Time.
The idea of daylight saving time was first conceived by Benjamin Franklin in 1784 during his stay in Paris.
He published an essay titled “An Economical Project for Diminishing the Cost of Light” that proposed to economize the use of candles by rising earlier to make use of the morning sunlight.

In 1895 Modern DST was proposed by entomologist from New Zealand, George Vernon Hudson.
Hudson presented a proposal for a two-hour daylight saving shift to the Wellington Philosophical Society.
He proposed to a two-hour shift forward in October and a two-hour shift back in March. He followed up his proposal with an article in 1898.
But no one followed his idea.

In year 1905 an English builder William Willett suggested the idea of moving the clocks forward in the summer to take advantage of the daylight in the mornings and the lighter evenings.
He suggested moving the clocks 20 minutes forward each of four Sundays in April, and switching them back by the same amount on four Sundays in September.

This time the idea of William Willett got the attention of Robert Pearce.
He liked his idea.
In February 1908 Robert Pearce introduced a bill to the House of Commons
In 1909 the first Daylight Saving Bill was drafted. After that it was presented to the Parliament many times and examined by a select committee but because of opposition the bill remained bill and did not become the law.

Willett died in 1915 without seeing the success and acceptance of his idea but his idea is still alive keeping him alive.

The start of DST – Coming of DST and World War

In April 1916 during World War I to save the fuel Germany first time adopted DST.
When United Kingdom Britain saw Germany using DST, UK also accepted DST and other European nations also accepted DST.

During World War I to save energy, fuel countries started to use DST.
After world war was over few countries again started to use Standard Time but when World War II started those countries again started to use the DST.

During the World War II, it proved that DST saves the fuel or energy.
During World War II Double Summer Time was applied in Britain.
Double Summer Time moved the clocks two hours ahead of GMT during the summer and one hour ahead of GMT during the winter.

The term “winter time” is used for standard time.

The term “summer time” is used in various bills and Acts about DST in the United Kingdom.
Example - Summer Time Act of 1916


1945 to 1966 – In this period DST caused confusion as it was not compulsory for the states to follow the DST time.
Confusion for travelers, bus and trains and broadcasting industry or say radio.

From February 9, 1942 to September 30, 1945 President Franklin D. Roosevelt instituted year-round DST in the United States, called “War Time”
The law was enforced 40 days after the bombing of Pearl Harbor
During this time, time zones were called “Eastern War Time”, “Central War Time”, and “Pacific War Time”.

After the surrender of Japan in mid-August 1945, the time zones were relabeled “Peace Time”.

To the over the confusion, Congress passed Uniform Time Act of 1966 that stated DST would begin on the last Sunday of April and end on the last Sunday of October.
However, states still had the ability to be exempt from DST by passing a local ordinance.

The US Congress extended DST to a period of ten months in 1974 and eight months in 1975, in hopes to save energy.
The trial period showed that DST saved the equivalent in energy of 10,000 barrels of oil each day.

Countries always keep changing the DST time.

The DST schedule keeps changing and now in USA The current schedule began in 2007 and follows the Energy Policy Act of 2005, which extended the period by about one month where DST starts on the second Sunday in March and ends on the first Sunday in November.

Which American states do not follow DST?
the states of Arizona and Hawaii, and the US insular areas of Puerto Rico, the US Virgin Islands, American Samoa, and Guam.

U.S. Daylight Saving Time - Time Table

1. Year Spring Forward Fall Back

2. 2011 2 a.m. March 13 2 a.m. Nov. 6

3. 2012 2 a.m. March 11 2 a.m. Nov. 4

4. 2013 2 a.m. March 10 2 a.m. Nov. 3

5. 2014 2 a.m. March 9 2 a.m. Nov. 2

6. 2015 2 a.m. March 8 2 a.m. Nov. 1

7. 2016 2 a.m. March 13 2 a.m. Nov. 6

In non-equatorial Brazil, DST starts the first Sunday in November and ends the third Sunday in February.

In the European Union, DST starts the last Sunday in March at 1 am UTC and ends the last Sunday in October at the same time.

In Russia, the clock is set ahead beginning the last Sunday in March at 2 am local time and set back the last Sunday in October at the same time. Because the clock is already set an hour ahead of standard time, Russians effectively have two more hours of daylight in the summer.

In Israel and the area of Palestine, Daylight Saving Time is observed, but the time of change is decided every year.

Australia's DST starts the last Sunday in October and ends the last Sunday in March.

However, Tasmania's DST starts the first Sunday in October along with New Zealand and ends the last Sunday in March. New Zealand ends the third Sunday in March.

But now the time has come to keep the same time and educating kids in the school to use time properly.

During the war time India used the DST.
Currently India does not follow DST.

Reality views by sm –

Monday, December 12, 2011

Tags – DST Meaning DST simplified


aativas December 12, 2011  

Very informative but bit complicated. I have observed in Ramkrishna Mission (and I am sure it must be at many more places) the following instruction. Not exactly the same but it reads something like this
Darshan time:3.00 to 6.00 from November to March
4.00 to 8.00 from April to October

This looks much more simpler. People get one hour instead of declaring DST. Why can't all office timings change like this?

Kirtivasan December 12, 2011  

Thanks for such an important information. I had no idea about this.
You are very high in knowledge,SM. Very high.

kalaiselvisblog December 12, 2011  

am 2 not aware of dis... but a very nice information about DST...

u always giving as very nice information which is necessary 2 know... thanks 4 sharing...

Bikramjit December 12, 2011  

very informative .. but dont need it now do we :) i get ot sleep one hour less when it changes


sm,  December 12, 2011