'Winter time' is to officially begin this weekend with the clocks going back by one hour on Sunday morning.
At 2am on Sunday, clocks will go back by one hour to 1am although most smartphones, tablets and computers will update automatically.
Earlier this year, MEPs voted to scrap the practice of moving clocks forward by an hour in spring then back again in the autumn in the EU from April 2021.
The vote is not the last word on the issue but will form the basis of discussions with EU countries to produce a final law.
The practice of switching the clocks was first introduced in World War I to save energy by prolonging evening daylight in summer.
Last year, the European Commission proposed ending the practice after an EU-wide opinion survey showed a large majority in favour of doing so.
The survey generated 4.6 million responses, with 84% of respondents wanting to end seasonal clock changes.
Critics say the survey was dominated by Germans, who made up 70% of the respondents.
The seasonal time shift has also been the subject of debate in the United States where legislators have tried unsuccessfully to abolish it.
For now, Hawaii and most of Arizona do not follow the practice of adjusting clocks since World War II.
Russia decided in 2011 to switch to permanent summer time in an attempt to improve citizens' well-being but shifted to permanent winter time in 2014 after public complaints.
The majority of countries outside Europe and North America do not adjust their clocks.
