Clocks Change: Daylight Saving Time Ends in Many Countries

Across much of the world, countries are preparing to move their clocks back as standard time returns, ending the period of daylight saving time, during which clocks were set an hour ahead to extend evening daylight.

The shift means that people will, in theory, gain an extra hour of sleep, while the timing of sunrise and sunset will shift accordingly. However, not all regions observe this practice.

Decisions about clock changes are not made globally; instead, each continent, and frequently each individual country, sets its own policy. As a result, the timing and existence of such changes vary widely around the world.

Notably, countries such as Japan and China do not change their clocks at all, maintaining a single, fixed time zone throughout the entire year regardless of season.

Health experts have pointed to the impact that shifting clocks can have on the circadian rhythm, the internal biological process that regulates the sleep-wake cycle. Disruption to this rhythm, even by just one hour, has been linked to temporary effects such as fatigue and difficulty sleeping.

The practice of adjusting clocks twice a year, commonly referred to as the clock change, remains a subject of ongoing debate in several parts of the world, including within the European Union, where discussions about abolishing the system have taken place in recent years.

Supporters of ending the biannual clock change argue that a fixed, unchanging time would simplify daily life and reduce the health disruptions associated with the transition. Critics, meanwhile, point to the practical and economic reasons the current system was introduced in the first place, including energy savings linked to daylight use.

As the debate continues, the contrast between regions that change their clocks and those, like Japan and China, that maintain a constant time year-round highlights the lack of international consensus on how best to manage time itself.