PlayInfoBox

Home /Education /Daylight Saving Time (Summer Time) Explained

Daylight Saving Time (Summer Time) Explained

Here's what daylight saving time is, why it exists, and why the debate over keeping it never quite ends.

Why daylight saving time was introduced

Daylight saving time shifts clocks forward by one hour during the summer months, when daylight arrives early, so that daylight lasts later into the evening and less energy is spent on artificial lighting. Actual energy savings vary a lot by country, and research findings are mixed.

Which countries observe it and which don't

Most of the United States, Canada, and many European Union countries observe daylight saving time, while countries such as South Korea, Japan, China, and India, many of them closer to the equator or with less seasonal variation in daylight hours, do not.

South Korea's past experience with daylight saving time

South Korea observed daylight saving time on and off from 1948 through the 1960s, and again briefly around the 1988 Seoul Olympics, but has not used it since.

The case for daylight saving time

Supporters argue that longer evening daylight boosts leisure activity and spending and reduces traffic accidents, though many studies find the actual effect varies by region and lifestyle.

The case against daylight saving time

Critics point to disrupted sleep and body clocks around the twice-yearly change, technical glitches in computer systems during the transition, and energy savings that may not be worth the disruption.

The recent push to abolish daylight saving time

The European Union has debated scrapping the twice-a-year clock change multiple times, citing the inconvenience and questionable real-world benefit, though discussions about how individual member states would implement this continue.

Daylight saving time isn't just a US and Europe thing

Daylight saving time gets the most attention in US and European news, but many other countries, including South Korea, have experimented with it in the past. Looking at why it was introduced and weighing its pros and cons helps explain why some countries eventually dropped it.

Remembering which way the clocks move

The simplest way to remember the direction of the change is 'spring forward, fall back': clocks move forward one hour when daylight saving time begins in spring, and back one hour when it ends in autumn. Because the change usually happens at 2 a.m. local time, most people only notice the shift when they wake up the next morning.

Frequently Asked Questions

Is South Korea planning to bring back daylight saving time?

There have been several rounds of discussion about reintroducing it, but South Korea currently does not observe daylight saving time, and any decision to bring it back would be up to the government and National Assembly.

Are daylight saving time and standard time different things?

Yes. Standard time is the official reference time a country or region normally uses, while daylight saving time temporarily shifts that standard time forward by one hour.