aikavyöhykeajasta

Aikavyöhykeajasta, commonly known as daylight saving time (DST) or summer time, is the practice of advancing clocks during warmer months so that darkness falls at a later hour of the day. The purpose is to make better use of daylight. In most places that observe it, clocks are set forward by one hour in the spring and then set back by one hour in the autumn.

The concept of adjusting clocks to take advantage of daylight was first proposed by Benjamin Franklin in 1784, though his suggestion was more satirical than serious. Modern DST was first implemented in Germany and its allies on April 30, 1916, during World War I, as a measure to conserve coal. Many other countries followed suit.

The practice has been controversial. Proponents argue that it saves energy, reduces traffic accidents and crime, and provides more opportunity for outdoor recreation. Opponents contend that it disrupts sleep patterns, negatively impacts health, and provides minimal energy savings, with some studies even suggesting increased energy consumption.

The specific dates for the beginning and end of DST vary by country and region. In the European Union, DST starts on the last Sunday in March and ends on the last Sunday in October. In the United States and Canada, it begins on the second Sunday in March and ends on the first Sunday in November. Some countries and territories do not observe DST at all. The debate over its usefulness and impact continues in many places, and some regions have considered or implemented permanent DST or a return to standard time.