As most of Europe prepares to set clocks forward an hour on March 29, millions will brace for the biannual ritual of daylight saving time (DST) . DST is mostly observed in temperate regions, where the contrast between long summer days and short winter ones makes shifting time seem useful. For newcomers to these parts of the world, DST could be bewildering at first. If you miss a meeting or arrive too early at an event, you may be gently reminded with the mnemonic: "Spring forward, fall back" — denoting clocks being moved forward one hour in spring, and back one hour in autumn. In the Northern Hemisphere, this typically happens in March and October respectively, while Southern Hemisphere countries like Australia, New Zealand and Chile observe it in reverse, with time springing forward in September or October and falling back in April.…