96 Fun Facts About Daylight Saving Time

Which mnemonic reminds you which way to move the clocks?

'Spring forward, fall back': clocks jump ahead an hour in spring and drop back an hour in autumn, the season Americans call fall.

Which US federal department oversees time zones and daylight saving observance?

The Department of Transportation regulates US time zone boundaries and daylight saving observance, a duty inherited from the Interstate Commerce Commission; states petition it to move between zones.

Which countries were the first to adopt daylight saving nationally, on 30 April 1916?

Germany and Austria-Hungary moved their clocks forward on 30 April 1916 to conserve wartime coal; Britain followed on 21 May the same year.

Which Ontario city was among the first in the world to enact daylight saving, in 1908?

Port Arthur, on Lake Superior, moved its clocks forward in 1908, eight years before any country did; in 1970 it merged with neighbouring Fort William to form Thunder Bay.

What did Benjamin Franklin's satirical 1784 Journal de Paris letter actually propose?

Taxing shutters and firing cannons at dawn were among his mock remedies for Parisians who slept through the morning sun; Franklin never suggested moving the clocks.

William Willett is said to have had the idea for daylight saving while doing what?

Riding early and seeing blinds still down near Petts Wood is said to have convinced Willett that summer mornings were being wasted; his 1907 pamphlet was called The Waste of Daylight.

What clock change did William Willett propose in his 1907 pamphlet?

80 minutes, in 20-minute steps on four April Sundays, was Willett's 1907 scheme; he died in 1915, a year before Britain adopted a simpler one-hour change.

Which rock frontman is William Willett's great-great-grandson?

Chris Martin of Coldplay is a direct descendant of Willett, the Chislehurst builder whose 1907 pamphlet The Waste of Daylight launched the campaign for lighter evenings.

The United States first adopted daylight saving time in which year?

The Standard Time Act of 1918 introduced daylight saving and confirmed the US time zones; Congress repealed the clock change in 1919 over President Wilson's veto.

What did Franklin D. Roosevelt call the year-round daylight saving he instituted in February 1942?

War Time kept American clocks an hour ahead all year until September 30, 1945, and the zones themselves were renamed, so New York ran on Eastern War Time.

Which 1966 law first standardised the start and end dates of daylight saving across the United States?

The Uniform Time Act ended the patchwork in which states and even towns picked their own dates, while letting a state exempt itself entirely by law.

Why did the US cut short its 1974 trial of year-round daylight saving?

Pitch-dark winter mornings, with children heading to school before sunrise, cut public support from 79% to 42% in three months, and Congress ended the trial that October.

Which US law, effective 2007, extended daylight saving to run from March to November?

The Energy Policy Act of 2005 added about a month of daylight time from 2007, and Congress kept the right to switch back if the promised energy savings failed to appear.

Besides Arizona, which US state stays on standard time all year?

Hawaii opted out in 1967, a year before Arizona, so for most of the year Honolulu sits three hours behind Los Angeles and for the rest only two.

Which territory inside Arizona does observe daylight saving time?

The Navajo Nation keeps daylight time because it also spreads into Utah and New Mexico; the Hopi Reservation it encloses does not, making a doughnut of clocks inside Arizona.

Why does Arizona stay on standard time all year?

Its heat makes evening sun unwelcome: an extra hour of summer daylight means more air-conditioning, so the legislature opted out in 1968, and from March to November most of Arizona matches California's clock.

Which US state did not observe daylight saving statewide until April 2006?

Indiana left most of its Eastern-zone counties on standard time until April 2006, though a few near Louisville and Cincinnati had long changed their clocks unofficially.

How did the Sunshine Protection Act, making daylight saving permanent, pass the Senate in 2022?

By unanimous consent, in March 2022: several senators said afterwards they would have objected had they known it could pass, and the House let the bill expire that year.

Since 1996, when have all EU countries changed their clocks together?

Last Sundays of March and October, fixed by an EU directive that took effect in 1996 after years in which the autumn date varied between member states.

A 2018 EU public consultation on scrapping the clock change drew how many responses?

4.6 million replies arrived during the six-week web survey in summer 2018, and within a month of its close the Commission proposed ending the twice-yearly change.

What became of the European Parliament's 2019 vote to end seasonal clock changes?

The Council never approved it: member states could not agree whether to keep summer or winter time, so the plan was still stalled in 2026.

Which of these European countries keeps the same clock all year, never springing forward?

Iceland sits on GMT all year despite lying far enough west for UTC-1, which gives it light summer evenings anyway; Ireland, Norway and Portugal all shift their clocks.

What did Russia do in 2011, then reverse in 2014?

Adopt permanent daylight saving time: the clocks went forward in March 2011 and stayed there until October 2014, when Russia moved back an hour and kept standard time from then on.

What was the 1941–1945 UK scheme of running clocks two hours ahead of GMT called?

British Double Summer Time put clocks at GMT+2 each summer from 1941 to 1945; Britain later tried year-round GMT+1 from 1968 to 1971 as 'British Standard Time' and abandoned it.

Which parts of Australia stay on standard time all year?

Queensland, NT and Western Australia: Queenslanders voted daylight saving down with a 54.5% 'no' in 1992 after a three-year trial, and Western Australia gave it up for good in 2009.

When do Australia's daylight saving states put their clocks forward each year?

First Sunday of October, running to the first Sunday of April: until 2008 only Tasmania started that early, while the mainland states waited for the last Sunday of October.

Lord Howe Island, off Australia, is unusual for a daylight saving shift of how much?

30 minutes: Lord Howe Island moves from UTC+10:30 to UTC+11, so in summer it shares Sydney's time and in winter runs half an hour ahead of it.

Which country kept its clocks an hour ahead from 2018 to 2026, pausing only for Ramadan?

Morocco made GMT+1 its year-round time in October 2018 and dropped back to GMT only for the fasting month, until it returned to GMT for good in September 2026.

Which country switched to permanent daylight saving time in 2016 rather than changing clocks?

Turkey kept its summer clocks on for good in September 2016, so it shares Moscow's time all year and runs an hour ahead of neighbouring Greece every winter.

Which country abolished daylight saving nationwide in 2022, apart from some border areas?

Mexico ended its nationwide clock change in October 2022, keeping it only in Baja California and towns along the US border so they stay in step with their American neighbours.

Which South American country used daylight saving on and off from 1931 until ending it in 2019?

Brazil first tried daylight saving in 1931 and ran it every summer from 1985 until President Bolsonaro scrapped it by decree in April 2019, saying it no longer saved much energy.

A 2014 study of Michigan hospitals found a jump in what on the Monday after clocks spring forward?

Heart attacks rose by about a quarter on the Monday after the spring change, then fell by 21 percent on the Tuesday after clocks went back in autumn.

Which interests have historically lobbied in favour of daylight saving time?

Retail, sports and tourism gain from light evenings and pushed for it, while farmers and cinemas fought it, which turns the 'it was for the farmers' story on its head.

Why is daylight saving of little use near the Equator?

Day length barely varies through the year at the Equator, about 12 hours of sun every day, so there is no seasonal evening light to shift; almost no African or South-East Asian country bothers.

Which US president signed the law that put America on year-round daylight saving from January 1974?

Richard Nixon signed the two-year emergency trial in December 1973, during the oil crisis, and the clocks went forward on January 6, 1974; Congress ended it early that October.

Which Antarctic research stations run on New Zealand time, daylight saving included?

McMurdo and Amundsen-Scott are both supplied by US flights from Christchurch, so the two American bases simply keep New Zealand's clock, daylight saving included.

At what local time do US clocks change on daylight saving days?

2:00 a.m. local time, chosen to minimise disruption: in spring 2:00 a.m. becomes 3:00 a.m., and in autumn the hour from 1:00 to 2:00 a.m. happens twice.

Britain first put its clocks forward in May 1916 under which piece of legislation?

The Summer Time Act was rushed through Parliament in May 1916 and the clocks went forward on 21 May, a year after the death of William Willett, who had campaigned for it.

How many time zones does Russia span?

11 zones, from UTC+2 in Kaliningrad to UTC+12 in Kamchatka; a 2010 reform abolished two of them, but the count has since returned to eleven.

Which Antarctic research station shifts its clocks two hours at once, between GMT and CEST?

Troll, Norway's base in Queen Maud Land, runs on Central European Summer Time from March to October, the months of Norway's own summer time, and on GMT for the rest of the year, skipping the one-hour step.

Which industry lobbied for US daylight saving to stretch into early November from 2007?

Candy makers had lobbied for years to bring Halloween trick-or-treating into daylight; the extension moved the end of daylight time to the first Sunday of November, just past 31 October.

What is unusual about Ireland's legal 'standard time'?

It is the summer clock: a 1968 act made GMT+1 Ireland's standard time, and a 1971 amendment treats the months on Greenwich Mean Time as a 'winter time' exception.

A meta-analysis of 44 studies found daylight saving cuts electricity use by roughly how much?

0.3% was the average saving found across the 44 studies, tiny because lighting's share of electricity use has fallen while heating and air conditioning can offset any gain.

A 2000 study tied the Monday after each clock change to a drop in what?

US stock markets: Kamstra, Kramer and Levi tied sleep-short traders to weaker Monday returns after each clock change, though later researchers disputed their method.

Before 2013, which holy day did Israel deliberately end daylight saving ahead of?

Yom Kippur: Israel's 2005 law ended daylight saving on the Sunday before the fast so it would finish earlier in the evening; a 2013 law moved the end to the last Sunday of October.

What is IANA's catalogue of historical and predicted clock shifts, used by most Unix systems, called?

The tz database, also called zoneinfo or the Olson database, catalogues every zone's rules; North America's 2007 rule change forced a wave of updates to calendar and email software.

Which group, often wrongly credited with inspiring daylight saving, has been among its strongest opponents all along?

Farmers work by the sun, not the clock: dew still has to dry and dairy cows are ready for milking at the same solar hour, so the shift only cut their time to reach market.

Idaho's two senators backed a longer US daylight saving season believing fast-food chains would sell more of what?

French fries are made from Idaho potatoes, and the lobbyist for the 1980s extension later told Congress that was how he won both of the state's Senate votes.

A 2017 study found which professionals turned measurably harsher at work after losing sleep to the spring clock change?

Judges in US federal courts handed down longer sentences when the switch had cost them sleep, researchers at two American universities reported.

Which country revived daylight saving in 1987 and 1988 so the Olympics it hosted suited American television?

South Korea put its clocks forward so daytime events in Seoul could go out live in prime time on the US east coast, then dropped the practice once the Games were over.

Collisions between cars and which animal are said to jump 16% in the week after US daylight saving ends?

Deer strikes are part of a wider pattern: in Britain, road accidents rise by as much as 11% in the two weeks after the clocks go back.

Which kind of memorial to William Willett stands in Petts Wood, permanently set to daylight saving time?

A sundial is not his only local tribute: the Daylight Inn pub and a road called Willett Way are also named in honour of the campaigning builder.

Which future prime minister promoted William Willett's daylight saving plan as a young politician in Edwardian Britain?

Winston Churchill argued that lighter evenings would widen people's chances of health and happiness, but a parliamentary committee still narrowly rejected the plan in 1909.

Safety officials urge households to replace the batteries in which devices at each clock change, especially in autumn?

Smoke detectors get the reminder in autumn for a reason: that clock change falls just before the heating and candle season, when home fires increase.

Which country used daylight saving only from 1948 to the early 1950s, under Allied occupation, and never restored it?

Japan's own government abolished the summer clock in 1952, three weeks before the occupation ended, and later campaigns to revive it have all failed.

Along with prime-time television, which businesses are known to lose out from daylight saving's later sunsets?

Drive-in theaters need darkness to show a film, and evening-entertainment interests have opposed the clock change ever since theatre owners fought Willett's original plan.

Which country briefly ran on two rival times in March 2023 after its government delayed daylight saving at short notice?

Lebanon's phones switched automatically on the original date and several broadcasters refused to obey the delay, so the government backed down after days of mass confusion.

Which royal estate gave its name to the fast clocks King Edward VII kept to allow more evening light for hunting?

Sandringham time lasted until 1936, when Edward VIII scrapped it after the gap caused confusion during his father's final hours.

Which neighbouring US cities spent two weeks of May 1965 an hour apart over rival daylight saving dates?

Minneapolis and St. Paul split because the state capital switched early while its twin waited for the later date in state law, one of the muddles that led to federal rules in 1966.

Which US president twice vetoed the repeal of daylight saving after the First World War, only to be overridden?

Woodrow Wilson lost the fight in 1919 when lawmakers overrode his second veto, leaving each town free to choose its own summer clock for decades.

Which US president called daylight saving a deception and had federal staff start an hour earlier in summer 1922?

Warren Harding reasoned that people should simply rise and go to work earlier, but many businesses declined to copy Washington's 8 am start and the experiment was never repeated.

Which US president signed the 1966 law that gave American states one shared set of daylight saving dates?

Lyndon B. Johnson signed it at the urging of the transport industry, which had pressed for federal rules since 1962 because every town was choosing its own dates.

Which 1973 crisis led the United States to keep daylight saving running through the winter of 1974?

The Arab oil embargo made saving fuel urgent, so the clocks stayed forward from January 1974, though the trial was amended that October to bring standard time back for the next winter.

Fears for which group on dark winter mornings helped end America's year-round daylight saving trial in 1974?

Schoolchildren were setting off before sunrise, and after several fatal morning road accidents one state governor asked for the law to be repealed.

Which store chain joined Clorox in funding the coalition that won a longer US daylight saving season in the 1980s?

7-Eleven had a clear motive: Fortune magazine estimated in 1984 that seven more weeks of light evenings would bring its stores an extra $30 million.

Daylight saving campaigner William Willett disliked having to cut short which game when dusk fell?

Golf stood to gain from lighter evenings too: in the 1980s the National Golf Foundation estimated a longer season would add at least $200 million to the industry's revenues.

What was the title of the 1907 pamphlet William Willett published at his own expense to argue for moving the clocks?

The Waste of Daylight promised more than leisure: Willett calculated that lighter evenings would also save £2.5 million in lighting costs.

The first countries to adopt daylight saving nationwide, in 1916, wanted to conserve which wartime resource?

Coal shortages and air-raid blackouts drove the decision, and the same need to save fuel finally got Britain's long-stalled bill passed a few weeks later.

Romans fitted which timekeepers with different scales for different months, so summer daylight hours ran longer?

Water clocks let Rome divide daylight into twelve hours all year round, so one of those hours could last about 44 minutes in midwinter and 75 at midsummer.

Which vast country, officially on a single time zone, tried daylight saving from 1986 to 1991 before dropping it?

China is the largest country to keep one official time, set by Beijing, so in its far west the working day simply begins about two hours later by the clock.

Which country's voters rejected daylight saving in 1978, leaving it an hour behind its neighbours for half of 1980?

Switzerland gave in and adopted the summer clock in 1981, after six months out of step with every bordering country except tiny Liechtenstein.

A petition signed by 70,000 citizens of which country helped push the European Union to rethink clock changes?

Finland's parliament received the petition in 2017 and voted to ask Brussels to reconsider the twice-yearly switch, a year before the bloc proposed ending it.

Which Australian state brought back daylight saving in 1967 because of a drought, years before the others followed?

Tasmania has repeated the change every summer since, and until 2008 the southernmost state began its season weeks ahead of the mainland.

Which North African country scrapped daylight saving soon after its 2011 revolution, then reinstated it by law in 2023?

Egypt wavered in between: the summer clock returned briefly in 2014, and a planned 2016 comeback was cancelled three days before it was due to begin.

Which South American country tried daylight saving for a single year from 1992, when El Niño drought caused blackouts?

Colombia draws most of its power from hydroelectric dams, and dry reservoirs meant blackouts of up to ten hours a day; the clock change failed to help and was dropped.

Which Canadian province has largely ignored daylight saving since passing its own Time Act in 1966?

Saskatchewan commissioned a scientific study to settle the question, and it left most of the province on Central Standard Time all year, though by the sun it sits a zone further west.

Which part of Canada's far north stopped changing its clocks in 2020, staying on daylight time through winter?

Yukon's choice leaves its capital Whitehorse with solar noon close to 2 pm, in effect a double helping of daylight time.

Which Canadian province tried double daylight saving in 1988, moving its clocks two hours ahead for the summer?

Newfoundland has a long history with the summer clock: its Daylight Saving Act dates from 1917, three decades before it joined Canada.

Which US state's voters passed Proposition 7 in 2018, a first step toward keeping daylight saving all year?

California backed it with a 60% vote, yet nothing changed at once: the plan also needed two-thirds of the state legislature and a change in federal law.

Which US state passed its own Sunshine Protection Act in 2018, the model for the later federal bill of that name?

Florida's law was signed by Governor Rick Scott that March, but it could not take effect unless federal law let a state stay on summer time all year.

Which senator first introduced the federal Sunshine Protection Act in 2018 and kept refiling it for years?

Marco Rubio saw the bill clear the upper chamber in 2022 without committee review, and many colleagues said afterwards they had not known the vote was happening.

Under the 1966 federal rules, a US state could drop daylight saving alone, but who had to approve keeping it all year?

Congress wrote those rules with a single exit, staying on standard time, so state laws passed in favour of endless summer evenings were left waiting on federal action.

Which US city kept its own daylight saving after the 1919 repeal so its exchanges stayed in step with London?

New York wanted to preserve an hour of trading overlap with London, and Chicago and Cleveland then kept the summer clock simply to keep pace with it.

Bus drivers on West Virginia's Route 2 once reset their watches seven times in 35 miles entering which state?

Ohio and its neighbour had no shared rule before 1966, so each town on the run from Moundsville to Steubenville chose whether and when to move its clocks.

Opponents of daylight saving say shifting the clocks disrupts which human body cycle, raising the risk of heart attack?

Circadian rhythm can take weeks to adapt after a clock shift, which is why sleep-science societies would rather abolish the change and keep standard time all year.

William Christie, a leading opponent of William Willett's daylight saving plan, held which British post?

Astronomer Royal William Christie sided with the prime minister and the head of the Meteorological Office, and together they outweighed Willett's famous backers.

A study of three million records found that sleep lost to the spring clock change reduces which kind of giving?

Charity donations dipped after the change compared with states that never move their clocks, and brain scans linked lost sleep to a weaker urge to help others.

Which molten material spattered at a European plant in 1993 after a clock-change glitch cut its cooling time by an hour?

Steel was poured an hour too soon because the plant's timing computer followed a radio time signal straight through the changeover.

Daylight saving is thought to reduce which crime, because fewer potential victims are outdoors after dusk?

Robbery depends on finding people out in the dark, a point supporters of America's 1974 winter trial leaned on when they promised reduced crime.

Keeping Britain's clocks forward all winter is opposed by many in which nation, where sunrise could come after 10 am?

Scotland's resistance is strong enough that a 2005 bill proposed letting it and Northern Ireland opt out of any trial of lighter evenings.

The managing director of which London department store was an early backer of William Willett's daylight saving plan?

Harrods' chief joined a remarkable list of supporters that included the King and the manager of the National Bank, yet the plan was still voted down.

In the 1920s and 1930s, Britain set special rules so its clocks never changed on the morning of which festival?

Easter can still collide with the switch under today's fixed European dates, as it did in 2016.

What name was given to the 1930 measure that left every clock in the Soviet Union one hour ahead for decades?

Decree time began as a three-month shift to spread electricity demand, was extended indefinitely that autumn, and was only wound down from the 1980s.

Which South American country put its far-southern Magallanes region on summer time all year in 2017?

Chile had moved the whole country onto summer time in 2015, then reversed after complaints that included fruit growers reporting a 15% loss in productivity.

Which African country set its clocks back each winter from 1994 to 2017 rather than forward in summer?

Namibia scrapped the practice in 2017 mainly because it kept the country out of step with South Africa, its main trading partner.

William Willett died in 1915, a year before Britain first put its clocks forward, of which illness?

Influenza killed him at 58, and the idea he had paid to publish and lobbied for since 1907 became law only when wartime fuel shortages forced the issue.