What is Daylight Saving Time?

dst

Daylight Saving Time (DST), also known as daylight savings time, daylight time, or summer time, is the practice of moving clocks forward (usually by one hour) during the warmer months to ensure that darkness arrives at a later clock time. The typical implementation of DST involves advancing clocks by one hour in either late winter or spring (referred to as "springing forward") and then setting them back by one hour in the fall to return to standard time. This results in a 23-hour day in early spring and a 25-hour day in the middle of autumn.

Currently, fewer than 40 percent of countries worldwide observe daylight saving time switches, even though more than 140 countries have implemented them at some point. In the United States, only two areas adhere to permanent standard/winter time: most of Arizona and Hawaii. While many U.S. states switched to summer time this weekend, Mexico opted for permanent winter time for the first time, with some regions along the U.S. border and the northern half of Baja California choosing to continue observing daylight saving time.

When DST begins in the spring, you set your clock forward one hour (= lose one hour) and back one hour (= gain one hour). That's why we said "spring forward, fall back".
Many Northern Hemisphere countries, including North America, Central America, Europe, Asia, and northern Africa, use DST in the summer, but not all. Daylight Saving Time typically begins in March-April and ends in September-November, when the countries return to standard time, also known as winter time.
Many Southern Hemisphere countries, including Australia, New Zealand, most of South America, and southern Africa use DST starting the DST period in September-November and ending DST in March-April.
Less than 40% of countries worldwide adopt Daylight Saving Time (DST), primarily to maximize natural evening daylight. The impact of DST is most noticeable in regions located away from the Earth's equator. Some studies suggest DST can reduce road accidents by providing more daylight during peak traffic times, but other research raises concerns about its effects on public health. Additionally, DST aims to decrease energy consumption for artificial lighting in the evenings, though there is ongoing debate regarding its energy-saving effectiveness, with conflicting research findings.
In most cases, clocks are adjusted by one hour during Daylight Saving Time (DST). However, on Lord Howe Island, Australia, the clocks shift only 30 minutes forward from LHST (UTC+10:30) to LHDT (UTC+11) during DST. Throughout history, there have been various deviations, such as half-hour adjustments (30 minutes) or double adjustments (2 hours). Changes of 20 and 40 minutes have also been employed at times.

Blog

See more
loading