Daylight Saving Time
From Halbeeg, the open encyclopedia · Af-Soomaali
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Daylight saving time (DST) is a practice used by many countries in which the official time is advanced, usually by one hour, during the summer months, then returned to standard time when autumn arrives. The stated purpose is to align waking hours with daylight hours and reduce electricity consumption.
The practice is found mainly in countries at higher latitudes in the northern and southern hemispheres, where the difference between summer and winter day length is substantial. Countries near the equator—including Somalia and most of Africa—do not use it, because day length remains roughly constant throughout the year.
How it works
On the scheduled date in spring, official time is advanced by one hour: for example, 02:00 becomes 03:00. That day has 23 hours. In autumn, the practice reverses and the hour is moved back, making that day 25 hours long. The dates of these changes vary by region; there is no single worldwide standard.
Brief history
The idea of changing the clock to make better use of daylight emerged in the late 19th and early 20th centuries. Several countries adopted it extensively during World War I, motivated by the need to conserve fuel and save electricity. Subsequently, its use has been inconsistent: some countries abandoned it, others reinstated it, particularly during periods of high energy prices.
Debate
Supporters argue that extended evening daylight increases time spent outdoors, benefits business in sectors that profit from daylight, and reduces road accidents at dusk. Opponents contend that electricity savings are marginal and cannot be reliably measured, and that changing the clock disrupts sleep and travel schedules. Medical research remains divided on the effects of clock changes on sleep patterns.
Current situation
In recent years, several countries and regional authorities have debated ending the twice-yearly clock change, preferring to adopt a single permanent time. Such decisions require legal agreement and regional coordination, because time affects aviation, commerce, and computer systems.