Why do we have daylight saving time? The real history

We have daylight saving time because governments in World War I moved clocks forward an hour in summer to save fuel, and the habit stuck, which is why so many countries still do it. Daylight saving time, or DST, shifts an hour of daylight from the early morning, when most people sleep, to the evening, when they are awake. Germany was the first country to adopt it nationally, in 1916, to save coal. It was not invented for farmers, who were among its fiercest opponents.

In short

• DST was first used nationally by Germany and Austria-Hungary on 30 April 1916 as a wartime fuel-saving measure, and the United States followed in 1918.
• It doesn't create daylight; it moves the clock so sunset comes an hour later by the clock in summer.
• Studies find its energy savings are tiny or nil, sleep scientists favor ending the switch, and lawmakers disagree about which time to keep.

Was daylight saving time invented for farmers?

No. This is the most repeated myth about it. Farm work follows the sun and the animals, not the clock, and an hour's shift meant farmers had to deliver milk and grain an hour earlier by the sun to meet trains and buyers who kept clock time. In the United States, farm groups led the campaign that got national DST repealed in 1919, when Congress overrode President Woodrow Wilson's veto. The real supporters were city businesses, shops and sports, which gained an evening hour of light for customers.

Benjamin Franklin is the other false origin. In a 1784 letter to a Paris newspaper he joked that Parisians could save candles by getting up at dawn, and suggested firing cannons to wake them. He was teasing late risers, not proposing to change clocks.

Who came up with daylight saving time?

In 1895, the New Zealand entomologist George Vernon Hudson, who wanted more light after work to collect insects, proposed a two-hour summer shift to the Wellington Philosophical Society. The idea was mocked. In 1907, the English builder William Willett, annoyed that Londoners slept through summer mornings, independently published a pamphlet called The Waste of Daylight and campaigned for clocks to move in steps through April. Parliament debated it several times but didn't pass it before he died in 1915.

What turned the idea into law was war. World War I made coal precious, since it powered factories, ships and electric lighting. On 30 April 1916, Germany and Austria-Hungary moved their clocks forward an hour to cut the coal burned for evening lighting. Britain followed within weeks, and most of Europe soon after. The United States adopted it in 1918, in the same Standard Time Act that put the country's time zones into law.

How has daylight saving time come and gone?

DST has been switched on in crises and off when they passed. The US record shows the pattern most clearly.

Year	What happened in the United States
1918	DST begins with the Standard Time Act, as a wartime measure
1919	Congress repeals national DST over President Wilson's veto; cities and states keep it locally
1942–1945	Year-round "War Time" during World War II
1945–1966	A patchwork: towns, cities and states start and end DST on different dates
1966	The Uniform Time Act sets common start and end dates, while letting states opt out
1974	Year-round DST during the oil crisis, dropped before the next winter after complaints about dark mornings
2007	The Energy Policy Act of 2005 extends DST to the second Sunday in March through the first Sunday in November
2026	The House passes the Sunshine Protection Act, for permanent DST, on 14 July and sends it to the Senate

Today, according to the National Institute of Standards and Technology, DST in the US runs for about 238 days, around 65% of the year. Hawaii, most of Arizona, Puerto Rico, Guam, the US Virgin Islands, American Samoa and the Northern Mariana Islands don't use it. Arizona's exception has an exception of its own: the Navajo Nation, inside Arizona, does.

What does an hour's shift actually change?

The shift is easiest to see in one city. Here are approximate sunrise and sunset times for New York City at the two solstices under the three choices people argue about: switching twice a year, as now; standard time all year; and DST all year.

New York City	Switching, as now	Standard time all year	DST all year
21 June sunrise	5:24 AM	4:24 AM	5:24 AM
21 June sunset	8:30 PM	7:30 PM	8:30 PM
21 December sunrise	7:16 AM	7:16 AM	8:16 AM
21 December sunset	4:31 PM	4:31 PM	5:31 PM

The table shows the trade. Switching gives late summer evenings and keeps winter mornings from getting very dark. Permanent standard time keeps winter mornings light but brings summer sunrise before 4:30 AM. Permanent DST keeps sunset after 5:30 PM in December but means children walk to school in the dark until after 8 AM. Farther north and west within a time zone, the winter mornings get later still. That is what ended the 1974 experiment within a year.

Does daylight saving time save energy?

Barely, if at all. The original logic was lighting: an hour of evening light meant an hour less of lamps. But electricity now goes mostly to heating, cooling and appliances, which DST can make worse as well as better.

The US Department of Energy measured the four extra weeks of DST added in 2007 and reported to Congress that they saved 1.3 terawatt-hours of electricity, about 0.5% per day of the extension but only 0.03% of the year's electricity use. A study of Indiana, which adopted DST statewide only in 2006, came out the other way. The economists Matthew Kotchen and Laura Grant found that DST raised household electricity demand by about 1%, as more evening air conditioning in summer and more morning heating in autumn outweighed the saving on lights.

Is daylight saving time bad for your health?

The switch itself has measurable short-term costs, mostly from the lost hour of sleep in spring and the misalignment between the clock and the body's daily rhythm. In its 2020 position statement, the American Academy of Sleep Medicine pointed to studies linking the spring change to more heart attacks and strokes in the following days and to a rise of up to 6% in fatal car crashes in the US. It recommends ending clock changes and keeping standard time all year, which keeps the clock closest to the sun. More on why the body's clock matters is in why humans sleep. This note explains the research; it isn't medical advice.

Still argued

Almost everyone who studies the switch agrees that changing the clocks twice a year has costs. The argument is about which time to keep. Sleep scientists, including the American Academy of Sleep Medicine, favor permanent standard time, because morning light anchors the body clock and late winter sunrises disrupt it. Supporters of permanent DST, including the sponsors of the Sunshine Protection Act, point to more evening daylight for shopping, sports and outdoor activity, and to studies suggesting fewer crashes and robberies when evenings are lighter. The evidence on those evening benefits is more mixed than the evidence on the spring switch.

Why have some places dropped it?

Most of the world's countries don't use DST, especially those near the equator, where day length barely changes through the year; it is used mainly in Europe and North America and in a few countries of the far south, such as New Zealand. Several countries have stopped. Russia moved to permanent summer time in 2011, then, after complaints about dark winter mornings, switched to permanent standard time in 2014. Mexico ended DST for most of the country in 2022. China dropped it in 1991.

Elsewhere, the clocks keep changing because no one can agree on the alternative. The European Parliament voted in 2019, 410 to 192, to end seasonal clock changes, but EU governments have never agreed whether to stay on summer or winter time, so the proposal has stalled, as Euronews reported in October 2026. In the US, the House passed the Sunshine Protection Act, for permanent DST, by 308 votes to 117 on 14 July 2026. To become law it must also pass the Senate and be signed by the president. Under the law in force in 2026, DST ended on 1 November. How clock time is set, and argued over, is part of history that people live through twice a year.

Check yourself

• Why did the first countries to adopt DST do it during World War I, and why did farmers in the United States oppose it?
• Using the New York table, explain why permanent DST was abandoned after one winter in 1974.
• Why do modern studies find so little energy saving from DST, when the original idea was to save fuel?

Sources

• Daylight Saving Time — National Institute of Standards and Technology
• Impact of Extended Daylight Saving Time on National Energy Consumption, Report to Congress — US Department of Energy, 2008
• Does Daylight Saving Time Save Energy? Evidence from a Natural Experiment in Indiana — Kotchen and Grant, National Bureau of Economic Research, 2008
• Daylight saving time: an American Academy of Sleep Medicine position statement — Rishi et al., Journal of Clinical Sleep Medicine, 2020
• Roll Call 238, H.R. 139, Sunshine Protection Act — Office of the Clerk, US House of Representatives, 2026
• EU planned to scrap clock changes. Why are they still happening? — Euronews, 2026