Dylight Saving Time

Daylight saving time (DST), or summer time in British English, is the convention of advancing clocks so that evenings have more daylight and mornings have less. Typically clocks are adjusted forward one hour in late winter or early spring and are adjusted backward in autumn. Details vary by location and change occasionally; see When it starts and ends below.

DST affects businesses, traffic accident rates, and energy usage patterns, and it complicates computer-based systems.
Saving daylight was first mentioned in 1784 by Benjamin Franklin in a humorous letter[2] urging Parisians to save money by getting up earlier to use morning sunlight, thereby burning fewer candles in the evening. Franklin did not mention daylight saving time—he did not propose that clock time be changed. His letter was in the spirit of his earlier proverb "Early to bed and early to rise / Makes a man healthy, wealthy, and wise."[3]
The William Willett Memorial Sundial is always on DST.
The William Willett Memorial Sundial is always on DST.

In 1905 builder and outdoorsman William Willett invented DST in one of his pre-breakfast horseback rides. Willett had been dismayed by how many Londoners slept through the best part of a summer day. An avid golfer, he also disliked cutting short his round at dusk. Two years later he published a comprehensive proposal for DST,[4] which attracted many eminent supporters, including Balfour, Churchill, Lloyd George, and MacDonald. Edward VII also favored DST and had already been using it at Sandringham. However, Prime Minister Asquith opposed the proposal and after many hearings it was narrowly defeated in a Parliament committee vote in 1909. Willett's allies introduced new DST bills every year from 1911 through 1914, to no avail.

From Wikipedia