Hot Info: Daylight Savings

This article is about DST in general.

While the adoption of Daylight Saving Time is almost always rife with controversy, most of the world has implemented DST at one point or another.

Although not used by most of the world’s people, daylight saving time is common in high latitudes.

Daylight savings time, daylight savings, and daylight time are common variants, the savings by analogy to savings account.

In the future, the government will set the dates for daylight savings without congressional approval.

In this ancient water clock, a series of gears rotated a cylinder to display hour lengths appropriate for each day’s date.

Japan, India, and China are the only major industrialized countries that do not observe some form of daylight saving.

In response to the problems caused by the lack of uniformity, a Private Members Bill, the National Measurement Amendment Bill 1991, was introduced into Federal Parliament in May 1991 by Ron Edwards, Member for Stirling in WA, to define a national system of time zones and Daylight Saving Time for Australia and its external territories.

Britain, most of its allies, and many European neutrals soon followed suit; Russia and a few other countries waited until the next year; and the United States adopted it in 1918.

Adding daylight to afternoons benefits retailing, sports, and other activities that exploit sunlight after working hours, but causes problems for farming, entertainment and other occupations tied to the sun.

People who work across time zone boundaries need to keep track of multiple DST rules, as not all locations observe DST or observe it the same way.

China has had a single time zone since May 1, 1980, observing summer Daylight Saving Time from 1986 through 1991; they do not observe DST now.

The prominent English builder and outdoorsman William Willett conceived DST in 1905 during a pre-breakfast ride, when he observed with dismay how many Londoners slept through the best part of a summer day.

Clock shifts correlate with decreased economic efficiency.

Since the daylight hours are similar during every season, there is no advantage to moving clocks forward during the summer.

DST inherits and can magnify the disadvantages of standard time.

Daylight saving time is the convention of advancing clocks so that afternoons have more daylight and mornings have less.

Although not punctual in the modern sense, ancient civilizations adjusted daily schedules to the sun more flexibly than modern DST does, often dividing daylight into twelve equal hours regardless of day length, so that each daylight hour was longer during summer.

People must remember to change their clocks; this consumes time, particularly for mechanical clocks that cannot be moved backward safely.

The bulk of the electricity in Tasmania is generated by hydroelectric stations, causing an energy shortage in the drought of 1967.

In a typical case where a one-hour shift occurs at 02:00 local time, in spring the clock jumps forward from 02:00 standard time to 03:00 DST and the day has 23 hours, whereas in autumn the clock jumps backward from 02:00 DST to 01:00 standard time, repeating that hour, and the day has 25 hours.

Obviously it does not change the length of the day; the longer days nearer the summer solstice in high latitudes merely offer more room to shift apparent daylight from morning to evening so that early morning daylight is not wasted.

As Franklin’s 1784 satire pointed out, lighting costs are reduced if the evening reduction outweighs the morning increase, as in high-latitude summer when most people wake up well after sunrise.

As with zoneinfo, a user of Microsoft Windows configures DST by specifying the name of a location, and the operating system then consults a table of rule sets that must be updated when DST rules change.

At present, as a sign of independence from Israeli rule, the Palestinian National Authority uses a different schedule for Daylight Saving Time than Israel.

Western China, Iceland, and other areas skew time zones westward, in effect observing DST year-round without complications from clock shifts.

Most of North America shifts at 02:00 local time, so its zones do not shift at the same time; for example, Mountain Time can be temporarily either zero or two hours ahead of Pacific Time.

For example, in 1984 Fortune magazine estimated that a seven-week extension of DST would yield an additional $30 million for 7-Eleven stores, and the National Golf Foundation estimated the extension would increase golf industry revenues $200 million to $300 million.

In 1992, for example, Tasmania extended daylight saving by an additional month while South Australia began extending daylight saving by two weeks to encompass the Adelaide Festival.

After persuasion by the Tasmanian Government, all states passed legislation in 1971 for a trial season of daylight saving.