49 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 the first in the world to enact daylight saving, in 1908?

Port Arthur, on Lake Superior, put its clocks forward on 1 July 1908; it merged with neighbouring Fort William in 1970 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.

British builder William Willett got the idea for daylight saving while doing what?

Riding early and seeing blinds still down on a summer morning near Petts Wood convinced Willett that daylight was being wasted; his 1907 pamphlet was called The Waste of Daylight.

How much did William Willett originally propose advancing the clocks each spring?

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The Standard Time Act of 1918 introduced daylight saving and confirmed the US time zones; Congress repealed the clock change in 1919 over President Wilson's veto.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

It ran until September 1945; the zones were literally called Eastern War Time, Central War Time and so on.

Which 1966 US law first standardised the start and end dates of daylight saving across the country?

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.

What happened to public support for year-round daylight saving over the winter of the 1974 US trial?

It fell from 79% to 42% within weeks of the January 1974 start; dark mornings and reports of children struck by cars on the way to school ended the experiment that October.

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

The Energy Policy Act of 2005 set the change to the second Sunday of March and the first Sunday of November, taking effect in 2007.

For roughly what share of the year is the United States on daylight saving time?

About 65% of the year: 34 weeks or 238 days from the second Sunday of March to the first Sunday of November, leaving standard time the minority.

Which two US states do not observe daylight saving time?

Arizona and Hawaii opted out under federal law, Hawaii in 1967 and Arizona in 1968; Puerto Rico, Guam, American Samoa, the Northern Marianas and the US Virgin Islands also skip it.

Which territory inside Arizona does observe daylight saving time?

The Hopi Reservation, entirely surrounded by the Navajo Nation, does not - creating a doughnut of clocks within a doughnut.

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 straddles the Eastern and Central zones; several counties near Cincinnati and Louisville had quietly observed DST anyway.

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

By unanimous consent, on 15 March 2022, with several senators later admitting they had not noticed the request; sponsored by Florida's Marco Rubio, it then stalled in the House.

As of 2023, roughly what proportion of the world's countries use daylight saving time?

About a third, roughly 70 of the world's 195 or so countries, concentrated in Europe and North America; most of Asia and Africa never adopted it or dropped it.

On which dates have all EU countries changed their clocks together since 1996?

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, a record for an EU consultation; most came from Germany and 84 percent wanted the clock changes scrapped.

What happened to the European Parliament's March 2019 vote to end seasonal clock changes?

The Council never approved it: member states could not agree on whether to keep summer or winter time, so the file stalled after the Parliament's 2019 vote.

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: under President Medvedev the clocks went forward in March 2011 and stayed; in October 2014 Russia moved back an hour to permanent standard time.

What was Britain's 1941–1945 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 Australian states do NOT observe daylight saving?

Queensland, NT and Western Australia stay on standard time; Queenslanders voted daylight saving down 54.5 to 45.5 in a 1992 referendum after a three-year trial, and WA rejected it in 2009.

In the Southern Hemisphere, when does daylight saving run in the states of Australia that use it?

First Sunday of October to first Sunday of April, agreed by the participating states from 2008; Australians spring forward as Europeans fall back.

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

30 minutes: clocks go from UTC+10:30 to UTC+11 in summer, making Lord Howe Island one of the very few places with a half-hour change.

Which country observes daylight saving every month except one, pausing it for Ramadan?

Morocco made GMT+1 its standard time in October 2018 and drops back to GMT for the fasting month each year, so its clocks change twice annually around Ramadan.

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

Turkey stayed on UTC+3 year-round; Russia had tried the same thing from 2011 to 2014 and given up.

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

Mexico scrapped the clock change from October 2022, keeping it only in towns along the US border; Sonora had already dropped it in 1998, and Samoa ended daylight saving in 2021.

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 used it every summer from 1985 until President Bolsonaro abolished it by decree in April 2019.

A 2014 Michigan study found what rise in heart attacks the Monday after clocks spring forward?

About 24% more heart attacks were recorded on the Monday after the spring change in a 2014 University of Michigan study, with fewer than usual after the autumn change.

Which interests have historically lobbied FOR daylight saving time?

Retail, sports and tourism gain from light evenings, so golf and barbecue trade groups pushed for it; farmers and cinemas opposed it, making the 'for the farmers' myth backwards.

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 permanent daylight saving time into law in January 1974?

The energy-crisis experiment was meant to last two years and was cut short after one dark winter.

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, all kept on standard time year-round since 2014?

11 zones, from UTC+2 in Kaliningrad to UTC+12 in Kamchatka, restored in 2014 after a 2010 reform had merged them into nine.

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

Troll, Norway's base in Dronning Maud Land, keeps UTC in the dark months and jumps straight to Central European Summer Time, UTC+2, for the austral summer, skipping the one-hour step.

Which lobby pushed the 2005 US extension so that Halloween would fall within daylight saving?

Candy makers had lobbied for years to bring Halloween trick-or-treating into daylight hours; the 2005 extension moved the end date to the first Sunday of November, after 31 October.

At what UTC instant do all European Union countries change their clocks together?

01:00 UTC, so every member state jumps at the same instant and the gaps between European zones stay constant; North American zones each change at their own local hour.

How does Ireland's clock arrangement differ from most countries that observe daylight saving?

Its winter time is legally the offset, not summer: Irish Standard Time is UTC+1, and in winter Ireland moves to Greenwich Mean Time as a legal 'winter time', unlike Britain.

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.

One estimate put the daylight-saving effect's cost to US stock exchanges in 2000 at how much?

$31 billion in one day was the figure in a 2000 American Economic Review paper by Kamstra, Kramer and Levi, who linked sleep loss to weaker Monday returns; other researchers disputed the methodology.

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.