Daylight Calculator
Daylight saving time (DST; also summer time in British English) is the convention of advancing clocks so that afternoons have more daylight and mornings have less. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn; several ancient cultures lengthened each summer daylight hour instead. Modern DST was first proposed in 1907 by William Willett, and saw its first widespread use in 1916 as a wartime measure aimed at conserving coal. Despite controversy, many countries have used it since then; details vary by location and change occasionally.
Adding daylight to afternoons generally benefits retailing, sports, and other activities that exploit sunlight after working hours, but it can cause problems for farmers and others whose hours depend on the sun. Extra afternoon daylight appears to cut traffic fatalities; its effect on health and crime is less clear. DST is said to save electricity by reducing the need for artificial evening lighting, but the evidence for this is weak, and DST can boost peak demand, increasing overall electricity costs.
DST's clock shifts complicate timekeeping and can disrupt meetings, travel, billing, recordkeeping, medical devices, and heavy equipment; they also serve as fire safety reminders.Many computer-based systems can adjust their clocks automatically, but this can be limited and error-prone, particularly when DST rules change.
