On Sunday in North America, clocks are turning back to mark the end of daylight saving time.
What exactly is daylight saving time and how does it affect countries worldwide? Here’s what we know:
What is daylight saving time?
Daylight saving time is the practice of moving clocks forward by one hour during the summer months so that daylight lasts longer into the evening.
When does daylight saving time end?
- Daylight saving time will end on November 5 in the United States and neighbouring countries at 2am local time. Clocks will be turned back by an hour.
- It started on March 12 when clocks were turned forward in North America by an hour at 2am local time.
- Daylight saving time always starts on the second Sunday in March and ends on the first Sunday in November in North America.
- Daylight saving time has already ended in the UK and the European Union countries that use it on October 29 where it begins on the last Sunday in March and ends on the last Sunday in October.
What countries practise daylight saving time?
Most of North America and Europe including the United States, Canada and Cuba, follow the custom while the majority of other countries, especially those close to the equator, do not.
However, not all states and territories in the US follow the practice. Exceptions include Hawaii and most of Arizona – except for most of the Navajo Nation – which do not observe daylight saving time. American Samoa, Guam, the Northern Mariana Islands, Puerto Rico and the Virgin Islands also observe permanent standard time.
While daylight saving time is widespread across the US, 19 states have passed legislation to permanently use daylight saving time if Congress were ever to allow it, according to the National Conference of State Legislatures.
Outside the US, some other countries that don’t practice daylight saving time include Armenia, Azerbaijan, Belarus, Georgia, Iceland, Russia and Turkey.
The United Kingdom practises daylight savings and set its clocks back one hour on October 29. Australia winds its clocks forward by one hour on the first Sunday of October.
However, many countries worldwide have adopted and rejected it multiple times.
Egypt announced in March it would reintroduce daylight saving time after a seven-year gap to ration energy use.
Japan considered adopting the practice for the 2020 Olympic Games but rejected the proposal due to a lack of popular support and technical challenges.
What are the origins of daylight saving time?
The origins of the biannual changing of the clocks can be traced back to at least the late 19th century when New Zealand entomologist George Hudson proposed it to conserve energy and extend summer daylight hours, something which would have benefitted his own hobby of collecting insects after work.
The idea was slow to gain traction until the first world war when European states sought strategies to conserve fuel.
Germany was the first country to adopt daylight saving time in 1916 and the US followed in 1918.
The practice went through many variations before the US standardised it in 1966 in the Uniform Time Act, which allows states to opt out of it but not to stay on daylight saving time permanently.
A common myth is that the US adopted daylight saving time to benefit farmers, but in reality, many farmers are opposed to the practice for being disruptive to their schedules.
The original motivation to conserve fuel is also under debate, as studies have found little, if any, energy savings from the shift, according to the Congressional Research Service.
Opponents of the time change point to other studies that have found adverse health effects linked to daylight saving time, such as a spike in fatal traffic accidents, heart attacks, strokes and sleep deprivation in the days after clocks are moved forward an hour every March.
How did daylight saving time divide Lebanon?
This year, a dispute around daylight savings time deepened sectarian divisions in Lebanon. After Caretaker Prime Minister Najib Mikati issued a decision in March 2023 to delay entering daylight savings time on April 20, instead of March, the influential Maronite Church disregarded this decision and set its clocks forward. The move was made to support Muslims during the fasting month of Ramadan.
Other Christian organisations followed suit while Muslim institutions did not change their time. This seemed to deepen divides in Lebanon that witnessed a 1975-1990 civil war between factions and where parliamentary seats are allocated by religious sect.
Lebanon’s cabinet reversed Mikati’s decision and clocks were moved forward in late March.
Have countries tried to stop using daylight saving time?
The European Union: The EU voted in 2019 to end the biannual practice entirely by 2021, but the plan was put on hold due to the COVID-19 crisis.
United States: There was a similar effort in the US federal government to pass the so-called Sunshine Protection Act in 2022, which would make daylight saving time permanent, eliminating the need to change clocks twice a year.
Despite the Sunshine Protection Act, the US is not ending daylight saving any time soon.
The act, which a bipartisan group of senators introduced in 2022, was passed unanimously by voice vote but stalled in the US House of Representatives because lawmakers could not agree on whether to keep standard time or permanent daylight saving time, said Representative Frank Pallone in March.
The group of senators reintroduced the bill again this year and it has been referred to the Committee on Commerce, Science and Transportation for review. The bill would need to pass the Senate and House of Representatives before President Joe Biden can sign it into law.