Daylight saving time (DST)—also summer time in several countries,^{[1][2][3][4][5][6]} in British English, and European official terminology (see Terminology)—is the practice of advancing clocks so that evenings 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.^[7]

Though mentioned by Benjamin Franklin in 1784, the modern idea of daylight saving was first proposed in 1895 by George Vernon Hudson ^[8] and it was first implemented during the First World War. Many countries have used it at various times since then.