23

I came to France( in Lille) 1 month ago for doing masters. I adjusted all my clocks which are not connected to internet according to french time.

Today when I woke up, I noticed that all the clocks connected to internet are showing the time say 12:00 pm then all the clocks not connected to internet are showing the time 1:00 pm. Now all my clocks not connected to internet show a time 1 hour ahead of the time shown by the clocks connected to internet. I googled the time and the time shown by clocks connected to the internet is the time shown by google. I live in studio. So, has someone played a prank on me? I am sure No friends visited me during yesterday. By clocks connected to the internet I mean my mobile , my laptop.

How did the time has changed? This seems bizzare. ( I am not joking)

Is this a time zone thing I am not aware of?

Improve this question
4
  • When you arrived you adjusted all your clocks not connected to the internet to local time. The latest Daylight Saving Time change timeanddate.com/time/zone/france/paris means you need to do that again.
    – Traveller
    Oct 30, 2022 at 12:25
  • 11
    Where are you from? In most of Europe and North America, clocks are made 1 hour ahead in summer (day light saving time) to have day light till late hours. The clocks are now switched back.
    – Thomas Cruise
    Oct 30, 2022 at 12:33
  • 16
    Your clocks will show the correct time again on the 26th of March next year.
    – Berend
    Oct 30, 2022 at 12:51
  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Willeke ♦
    Nov 1, 2022 at 11:44

2 Answers 2

Reset to default
48

You just discovered Daylight Savings Time (DST), also called Summer Time.

During the winter, Metropolitan France is on UTC+1.

During the summer, from the last Sunday in March at 2am to the last Sunday in October at 3am, it switches to UTC+2.

The goal was to have more of the “active” part of the day with daylight, in order to save money on lighting. The savings are disputable nowadays, but it’s still like this. There have been plans for years to stop the twice-yearly change (and actually stay on summer time all year long), but they haven’t come to fruition yet.

So last night, at 3am, it was suddenly 2am again.

Devices which know about the actual time zone and associated changes (computers, phones, tablets, smartwatches…) will take the changes into account automatically. Others will have to be reset. I had to change 4 devices this morning.

DST is common in countries with a big difference in daylight duration between winter and summer (higher latitudes). It is indeed quite uncommon in the tropics where there is very little difference.

Of course, that means that the time difference with your country of origin has changed as well, since apparently in your country there is no DST.

Improve this answer
3
  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Willeke ♦
    Nov 1, 2022 at 12:47
  • 1
    "There have been plans for years to stop the twice-yearly change (and actually stay on summer time all year long)" the first part is correct, the parenthesised part not so much. As I've heard it the EU resolution is to get rid of the shifts by making each country choose for themselves if they want to be on normal time or summer time all year. With the possible consequence that neighbouring countries that used to have the same time, might end up being an hour apart, and if you travel through Europe you might have to set your watch several times.
    – Henrik supports the community
    Nov 8, 2022 at 16:38
  • @Henriksupportsthecommunity That was the result of a 2018 online opinion survey (4.6 million responses from a 513 million population - 4.65%) that was sponsered by the EU Commission. No member state has shown any interest whatsoever in implementing this recommendation. It was a dead duck from day 1.
    – Mark Johnson
    Nov 8, 2022 at 19:10
5

Not addressed in the accepted answer is that start and end of observing daylight saving may differ by multiple days e.g., between the U.S.A. and central Europe. Though there is the consent to spring forward/fall back* in the night of a Saturday to Sunday, central Europe (including France) adjusted the clocks per yesterday (Oct 30), while this time the US will keep the daylight saving up to Nov 6. Thus the difference between the time normal in e.g., Paris and Boston of typically six hours is not fix (i.e., currently 5h only). Voilà, you see one reason why e.g., weather bureaus and the aviation industry like their time stamps to refer to a different standard (UTC).

What is often not this much a nuisance when calling home across the ocean, these «special days» may be an issue for internet services to schedule and coordinate e.g., a slot of time to run a measurement/record data or meetings if the server happens to be on the other side of the pond.

*) Spring forward, fall back actually is a trick to recall how to adjust the mechanical clocks in March (season of spring) and October/November (season of autumn/fall) in both regions of the Northern hemisphere. It's a different story (more puzzling in some regard) in Australia with three time offsets for standard, and five offsets when states (except Western Australia, Northern Territory, and Queensland) observe daylight saving; as a result, on Poeppel, Cameron, and Surveyor-Generals corner you could observe New Year's Eve thrice.

Improve this answer
9
  • 1
    I think that this is not addressed in the accepted answer because it's far more detail than was asked for in the question. The OP had never heard of daylight savings time, the accepted answer was a beginners' level explanation of the key points.
    – djr
    Oct 31, 2022 at 19:48
  • 1
    Going further, countries in the southern hemisphere have the opposite rhythm, which means the time difference between Paris and Sydney for instance can be either 8, 9 or 10 hours depending on the day of the year. Also, some places do not switch even though they are surrounded by places which do, so depending on the time of the year they are on the time of either their western or eastern neighbours. Add to that places which have special time offsets during Ramadan (to achieve the opposite effect: less daylight in the evening).
    – jcaron
    Oct 31, 2022 at 21:10
  • 5
    "It's a different story (more puzzling in some regard) in Australia": it's neither particularly different nor puzzling in southern hemisphere places that observe daylight saving time. They put their clocks forward in the spring and back in the autumn just as in the northern hemisphere.
    – phoog
    Nov 1, 2022 at 7:32
  • @phoog Well, except Iceland and Russia, there are three time zones observing daylight saving: a) Portugal, Ireland, Great Britain in the West, b) Finland, Estonia, Latvia, Lithuania, Ukraine, Moldova, Bulgaria, Romania, Greece in the East, and c) centre. On the other hand, there are three time offsets in Australia for standard, and five when states except Western Australia, Northern Territory, and Queensland observe daylight saving; then the stripes parallel to longitude break. Not to speak about Poeppel, Cameron, and Surveyor-Generals corner where you then could observe New Year's Eve thrice.
    – Buttonwood
    Nov 1, 2022 at 16:48
  • Note that the US just passed a law that will end the daylight savings shifts starting next year. So for anyone reading this answer in the future, that part at least will soon no longer be a thing.
    – Darrel Hoffman
    Nov 2, 2022 at 17:29

You must log in to answer this question.