Summer time – known as daylight saving time in the United States – is the process of changing the clock so that, during the middle part of the year, evenings have more daylight and mornings less. Normally, clocks are moved forwards by one hour towards the end of the first quarter of the year and put back by one hour during the last quarter.
Arrangements concerning summer time are now regulated in EU law. In 1996, it was agreed that summer time should always begin and end on the same day – the last Sunday in March and the last Sunday in October – throughout European Union (and in the other countries of the European Economic Area (EEA)). However, within this constraint, member states are free to choose whether they use Greenwich Mean Time (GMT), GMT+1 or GMT+2 as their local time zone, depending on how far east or west they are located. The cumulative effect of enlargement has been to greatly extend the physical breadth of the Union. Because the sun rises in Cyprus some three hours earlier than in Ireland or Portugal, there would be no point any longer in attempting to make the EU into a single time zone, as some had suggested in the 1970s. Most of the member states are sufficiently compact that they only need to use one time zone, although the Canary Islands and the Azores are one hour behind Spain and Portugal respectively, because of their more westerly location. (The French overseas departments are obviously a case apart).
Summer time was first introduced by Britain and Germany in 1916, in order to maximise active daylight during the first world war. Some countries advanced their clocks by a further hour for the same purpose during the second world war. From 1968 to 1971, the United Kingdom conducted an experiment of staying on summer time throughout the year. There is a lively debate about whether the UK should align with most of continental Europe, by moving from GMT to GMT+1, in order to facilitate business, increase the convenience of travel and realise potential energy efficiency gains.
Copyright: Anthony Teasdale, 2012
Citation: The Penguin Companion to European Union (2012), additional website entry