Talk:Daylight saving time/Archive 1

Spring Forward, Fall Back

 * "The mnemonic "Spring forward, Fall back", tells how to reset clocks in the Northern hemisphere when the time switches."

Maybe I'm staying up too late... :-) ...but isn't this correct also for the Southern Hemisphere? That is, don't you advance one hour in the springtime, whenever spring occurs in your hemisphere? -- Rootbeer


 * I think so. Spring is always the lengthening of days. In other words, seasons are specific to a hemisphere, but months are the same everywhere. July is a Winter month in New Zealand, as strange as that sounds to northerners! -- Tarquin


 * It would be correct for both hemispheres, but for the fact that all English speakers in the Southern hemisphere say "autumn" rather than "fall". Except American tourists, of course. :) Tim Starling 04:24 Nov 28, 2002 (UTC)


 * Tim is right. But speaking as an Australian, I think it's very useful all the same (and I think Aussies all know that Fall is American for Autumn). Why isn't it in the article (any more)?


 * Singkong 6 July 2005 02:52 (UTC)

I second this. The mnemonic should be in the article, preferably in the first paragraph. It's the number one reason people would come to this article. (that, and the dates of the change, in America). —The preceding unsigned comment was added by 87.97.8.129 (talk • contribs).

Usefulness or lack thereof
It has always struck me as odd to "save" daylight in the summer months, when there's so much of it anyway! There are campaigns in the UK to switch to DST all year round, that is to switch to GMT+1, as in winter months schoolchildren walk home around 16:00 and this is just when night falls, the worst time of the day for visibility on the roads. -- Tarquin


 * Or, they could change the school schedules to a more appropriate time without changing every clock in the country. Am I the only one who thinks daylight saving time is like trying to reduce traffic accidents by recalibrating all the speedometers to make people think they're going faster than they really are? --Brion 02:25 Sep 10, 2002 (UTC)


 * My comments on this were edited a bit. I originally wrote "Campaigners in Britain would like the country to stay on BST all year round, or to adopt Central European Time". This was altered to read "Campaigners in Britain would like the country to stay on BST all year round, or in other words, adopt Central European Time". But that's not quite what I meant. I meant EITHER stay on fixed daylight saving time all year round, adding one hour to GMT, OR adopt European time, adding an extra hour to winter time and two hours to summer. - Lee M.


 * Fixed. - Patrick 22:26, 26 Oct 2003 (UTC)

5th Grade Americentric
"5th grade" - this should be changed to an age to be comprehensible to those of outside the USA. -- Khendon


 * Agreed. -- Tarquin

Usage error?
How is "Daylight Savings Time" not a usage error? It doesn't make any kind of grammatical sense! - Khendon


 * Does "savings account" not make any kind of grammatical sense? --Brion

Yes, it does. Savings is a noun meaning a fund of money - a savings account is an account of savings. Daylight Saving Time is the Time used to Save Daylight. What does Daylight Savings Time mean? - Khendon


 * So when the local supermarket offers me MAJOR SAVINGS, it's offering to give me a fund of money over 18 years of age? Daylight Savings Time is, obviously enough to anyone who can parse English, the Time when you make Savings in Daylight. --Brion

re: google searches; it's not enough to do a naive page count. Actually look at the results - searching for the with-s variant turns up many pages saying that the correct spelling is without-s. In any case, who decided any illiterate who can make a web page gets an equal vote? -- Khendon


 * If an overwhelmingly large portion of the population didn't say it that way, pedants wouldn't feel the need to combat it at every turn. And if "illiterates" aren't enough for you, how about a dictionary? --Brion


 * "savings" are things one stocks and keeps. Unless you're not telling us something, Brion, or should I say Doctor Who!, no-one can make "savings" of time. We are "sort of) saving it in the sense of avoiding its waste. -- Tarquin


 * That's what makes it so cruelly deceptive -- you may save an hour once a year, but you give it up again six months later. :) I'll point out that, whether "saving" or "savings", there's exactly as much daylight no matter what you do to your clock. You don't save squat. --Brion


 * The article cited the American Heritage Dictionary as giving the form "Daylight Savings Time". My copy (third edition, copyright 1992, ISBN 0-395-44895-6) lists "Daylight-saving time" (with hyphen, no "s").  So I removed the citation.  If a future citation is given, it evidently should include the precise edition. --NealMcB 02:06, 30 April 2006 (UTC)


 * The fourth edition of the American Heritage Dictionary lists "daylight-savings time" as a variant form. See here. --Keith111 12:50, 23 June 2006 (UTC)

- "pedants" is it neutral in english ?

Dictionaries aren't authorities on English usage either, Brion; most are overtly descriptive and not prescriptive in nature, and even those that aren't admittedly so are so in practice. All that aside, what's wrong with the present state of the article--it uses the preferred form "saving", and mentions that "savings" is commonly used but often considered wrong. Isn't that exactly what an article on the subject should do? --LDC


 * Exactly my point, Lee. Yes, the article is precisely correct -- now. Previously it was overtly prescriptive, saying The expression "Daylight savings time" (with the extra s) is a common usage error. One might as well say that "pop" in reference to a carbonated, sweetened beverage is a common usage error which occurs frequently in the Midwest... I'm not sure I've ever in my life heard someone say "daylight saving time" without the s. --Brion


 * Correct, incorrect. The fact is, the mechanism was originally called daylight saving time, but the only people who care if you say daylight savings time are pedants.  A real pedant, me for instance, would say that it should be daylight-saving time.  So, except for the tragedy of the missing hyphen, the article is perfectly correct as it stands.  Ortolan88


 * this seems to cover it. As Ortolan notes, it was originally sans s.  If we call things by their names, then the "s" would be nonstandard, since that is not how it is spelled. The highest authority would be the text of the legislation that imposed the system.

On one level, language is a system of rules, and if we are discussing "standard" and "non-standard," that is the level that our thoughts inhabit. Saying that a thing is "standard" because people commonly say it that way, nullifies the meaning of the idea. Those who think in this way--that description is prescription--should probably not concern themsleves with discussions of correctness, since they don't seem to believe that such a concept exists. Any discussion beyond this terms "standard-ness" should probably be broadened to general description vs prescription and posted in that forum. The battle could certainly be better fought in some other area. Try plural pronouns with singular antecedants or maybe "who" vs "whom." Good Luck. user:smallwhitelight


 * The highest authority, the US Code (15USC260a), does not even mention Daylight Saving Time&mdash;instead, it talks about the "advancement of time". However, the public law (99-359) (same ref), which changed the statute in 1986, does use the term "daylight saving time" (not capitalized), as does the Code of Federal Regulations (49CFR71.2), which uses the capitalized form. Regulations are a step below statutes, being written by the Executive Branch of the U.S. government and published in the Federal Register, with no input from Congress. But note that Public Law 93-182 (first ref) entitled the "Emergency Daylight Saving Time Energy Conservation Act of 1973" has no 's', but the Executive Order based on it entitles it the "Emergency Daylight Savings Time Energy Conservation Act of 1973", with an 's'! I'm assuming that these online sources faithfully reproduce the printed form. &mdash; Joe Kress 05:13, 3 October 2005 (UTC)

What say you now pedants? -sun

Date of intro in USA
Right now the article seems to state two different dates for the US introduction of DST: 1918 and 1942. Which one is correct?


 * It turns out both are correct. I've added much more background. -- Minesweeper 09:01 22 May 2003 (UTC)

Note that not every European country observes daylight saving time in the normal sense. Iceland is on constant +1 daylight saving time, which is important during the 4 hours of daylight we get around Christmas.

Anyone know the details of British double summer time (and also I believe German double summer time), that existed for part of the summer during WWII? Mintguy

Time zone source material
I'd like to get a set of rules for major population centers, especially for English-speaking areas (like Japan, where people study ESL).

I want to make some GPL software that tells the user what time it is in his friend or business associate's time zone, taking into account daylight saving time oddities.

Especially when right near boundary conditions, like the last week in March or first week in April, when one might not be sure whether the Other Person is observing the same rules.

I'm going to make the software not only give you the other fellow's local time, but also display whichever rules apply.

So, if I'm in New York and you're in Chicago in the middle of the summer, we're both using the same rules -- so nothing special, you're just an hour behind: my 5:00 P.M is your 4:00 P.M.

But if you're in Indiana, where some counties have opted out of DST...

Or if it's soon after midnight, the last weekend in October and NYC has just set its clocks back -- but you're in Denver and haven't set yours back...

Or Cuba, which "springs forward" an April 1st... or those puzzling folks in Europe who do it a week early each spring...

So, please add all this info to the article, or find me a nice juicy link and all add it myself! --Uncle Ed 16:51, 27 Oct 2003 (UTC)


 * Nice Juicy Link (TM): http://www.twinsun.com/tz/tz-link.htm -- Catherine 05:03, 1 Apr 2004 (UTC)

Time shifts
...going from 22pm/0/1/2/3am LST to 23pm/1/2/3/4am LDT simultaneously on the last Sunday in March, and back from 23pm/1/2/3/4am LDT to 22pm/0/1/2/3am LST on the last Sunday in October...


 * Call me stupid, but is there some new system of time we should be using that has 22pm and 23pm, and in which 23pm is equivalent to 0am? What have I missed? - Mark Ryan 04:52, 2 Dec 2003 (UTC)


 * I fixed the first, but do not understand "23pm is equivalent to 0am": one zone is skipped, because it does not apply. - Patrick 19:48, 2 Dec 2003 (UTC)


 * 22, 23, etc shouldn't be labeled am or pm, should they? The whole point is to avoid the ambiguity of 12-hour clock am/pm-ness....  The 24-hour clock article doesn't explicitly specify but doesn't use them either. Catherine 05:03, 1 Apr 2004 (UTC)


 * The latest version:
 * ...going from 22:00/00:00/01:00/02:00/03:00 LST to 23:00/01:00/02:00/03:00/04:00 LDT simultaneously on the last Sunday in March, and back from 23:00/01:00/02:00/03:00/04:00 LDT to 22:00/00:00/01:00/02:00/03:00 LST on the last Sunday in October...
 * is not much better, since there are only 4 time zones in Europe (West European Time, Central European Time, East European Time, and Moscow Time), not 5 – and they correspond to UTC, UTC+1, UTC+2, and UTC+3 (not -3, -2, etc....). Also, the abbreviations LDT, LST mean nothing in a European context. Have rewritten the paragraph -- Picapica 21:36, 19 July 2005 (UTC)

12 hour vs 24 hour again
User 81.225.47.48 changed Brazilian DST starts at 12:00AM of a October (rarely November) Sunday to Brazilian DST starts at noon of a October (rarely November) Sunday in order to be "less ambiguous". True, "noon" is less ambiguous than either "12:00 AM" or "12:00 PM" would be, but is this really correct? Most of the world switches to DST in the night; is Brazil an exception here?? There is no link to a Portuegues article on this topic, and the Spanish version is to brief to give any details. Btw, Brazil stretches over 3 time zones. If all of them change to DST at noon, that must be a mess...

Also, I don't think that going from ends at 2:00 AM on the last Sunday in October to ends at 2 :00 on the last Sunday in October helps "unambiguation". You could argue that such changes does not introduce any new ambiguity, since everybody will understand that the 24 hour clock is used, but my experience tells me that not everybody is used to the 24 hour clock. Aleph4 21:58, 16 Feb 2005 (UTC)

I went ahead and reverted 81.225.47.48's changes. 12:00 AM, although confusing to some, means exactly one thing, midnight.

History of DST in specific areas
I'm familiar with the "rules" of daylight savings time. However, I'm searching for specific answers about its observation in two locations in two different months and years. Can anyone tell me whether or not daylight savings time was observed in (1)Barbourville, Kentucky, USA (Knoxville County) in June of 1950, and (2)Shreveport, Louisiana USA in September of 1954? Or can anyone refer me to a source that has detailed information about which states, counties, or parishes chose daylight savings time during the years when the locals could choose for themselves (i.e., 1945-1966)? Any suggestions would be greatly appreciated.--Miranda Moore


 * You may want to take this to the Reference desk, where questions like this are better suited. Dysprosia 03:32, 17 Dec 2003 (UTC)


 * It's not cheap ($195), but there's a comprehensive book about the history of time changes by locale, designed for astrologers, of all things. (Maybe you can find an older edition on eBay or in used bookstores.) It is available by computer download here: http://astrocom.com/software/pcatlas.php  -- Catherine 05:03, 1 Apr 2004 (UTC)

== Sir Sanford Fleming -- first proposed daylight savings time, and not whoever the bloke in the article is. I'm not sure when he did it (sometime in the 1880's) or I'd fix it myself.
 * He was the one who invented it for the railroads, which ARE mentioned in the article. I'll add him in.  -- Catherine 05:03, 1 Apr 2004 (UTC)

Auto safety
Interesting to read about a "spike in the number of severe auto accidents". This is the opposite of the effect I've heard from DST proponents: it's usually claimed that DST saves lives, since many more people will commute during daylight, when it's safer to drive. (Anybody have a source for this?)

Also, the study I found that states that auto accidents spike due to DST (http://www.bnsf.com/media/articles/2004/04/2004-04-01-c.html?index=/media/articles/index.html) says that auto accidents dropped by the same amount when daylight savings ends (and people get extra sleep). So making a spike in auto accidents sound like a simple case-against sounds quite misleading.


 * There was one early study by Stanley Coren that indicated accidents went up when the clocks were set back and down when the clocks were set forward, but that finding has been overturned. I've added this link which should set the record straight. More on the history of the controversy can be gleaned from a comment and reply that took place in the New England Journal of Medicine in 1996. I can dig up the specific references if anyone wants them. TrulyTessa 15:55, 25 October 2005 (UTC)

DST
Can someone tell the server about a phenomenon called Daylight Savings Time, so I don't have so switch between GMT-5 and GMT-6 every time we have DST?


 * The specific date, direction, and amount of shift to "correct" for the changing light levels is very much location-specific; indeed, some places don't have any need of it at all. The server is in GMT (well, an approximation of UTC-1, AIUI); the clocks change but twice a year, and I'm sure that you can cope. In fact, I don't have it change, and use my head to do the offset instead (well, 'tis only an hour for me, so...).
 * James F. (talk)


 * It would be simple. There could be a check box that says "Please auto-correct my time shift for daylight savings time", so it would only do it if you wanted it to.   If there are different types of daylight savings times around the globe, it could have an option to select which type. Worth submitting a feature request for, I might do it soon if nobody else has.  &mdash; siro  &chi;  o  04:26, Aug 2, 2004 (UTC)


 * Over here in Israel, there is a vote taking place every year, that determines the DST shift in/shift out. Computer modelling of our politicians to predict what they are going to vote on would be mostly welcome. :-) Seriously, a common practice is using NTP to feed off a trusted server, and once it jumps, you know that the daylight savings jumped. The server is manually updated. Some systems just have some hardwired approximate default dates, so around the shift they give wrong time for about a month in the worst case. BACbKA 20:58, 2 Aug 2004 (UTC)
 * You use NTP to transmit local times and not UTC? Oh, the horror, the horror... David.Monniaux 14:07, 8 Aug 2004 (UTC)


 * Israel appears to define the start of DST in the common calendar and the end by the Hebrew calendar, which actually makes sense. Because of a Sunday to Thursday workweek, Israel starts and ends Friday. Henry Troup 22:09, 5 Apr 2005 (UTC)


 * Most open source Unix systems use a library produced by NIH that knows about virtually every set of timezone rules on earth and is capable of translating things like US/Eastern + an offset in GMT into the local time and date. This library is extremely well maintained, the timezone files cover almost all jurisdictions on the planet, and updates come out several times a year. The code is all open source. There is no reason not to use it. --Pmetzger 21:03, 3 Aug 2004 (UTC)

Xerox timezone converter app is down
The link Time Zone Converter is down as of 4 November 2004. I have hidden the same in the article. --Mahadevan T S 10:44, 4 Nov 2004 (UTC)

So how exactly is DST useful ?
Can the article have some statistics or have a link to some statistics that list out the sunrise and sunset times of major countries, for different months of the year. I live in the tropics, and haven't experienced DST. Hence its difficult for me to understand exactly how people (in the temperate zone) find DST useful and how it affects their daily life. Jay 10:05, 18 Feb 2005 (UTC)


 * I've lived in Hawaii most of my life (with no DST) but went to school in the U.S. Pacific Northwest, which is around 45 degrees north latitude. That far north, sunrise usually happens at around 05:00 (DST) and the sun sets at around 21:00 (DST)...that means that you could go for an evening stroll while it's completely lighted.  I'm sure there are some calculators around that allow you to calculate sunrise and sunset given latitude and longitude...  KeithH 07:28, 25 Mar 2005 (UTC)


 * The big advantage of DST is that it "transfers" an hour or so from early in the day when few people are up and about to the evening, when activity is high. In effect there is a "free" hour of sunlight, with consequent savings in electicity usage. During WW2 the UK experienced double DST, when the clocks were advanced two hours rather than one, to take advantage of the very long hours of sunlight in high summer. Personally, I enjoy the long summer evenings, and it is pleasant to take a stroll or have a relaxing drink outside at that time of year, using time that would otherwise be dark. A disadvantage for parents of small children is that it can be harder to get them to sleep while the sun is still quite high in the sky. Pete 08:55, 23 May 2005 (UTC)


 * Instead of companies changing from 9-to-5 to 8-to-4 in the summer, the government adjusts the entire clock, which helps get rid of the public's perception of "oh no, we're waking and sleeping too early!"4.232.102.207 20:10, 22 July 2005 (UTC)

When you're tired in the middle of October, suddenly one Sunday you get an extra hour in bed! & you don't have to worry about any consequences of it 'til April! Dave 05:38, 2 May 2006 (UTC)

I challenge a statement made in the main article
Some campaigners in Britain would like the country to stay on British Summer Time (BST) all year round, or in other words, adopt Central European Time and abolish BST. &hellip; This would make winter evenings longer, thereby reducing traffic accidents and cases of seasonal affective disorder.

It wouldn't necessarily reduce SAD. I suffer from it, and for me the biggest problem is the darkness in the morning. Many SAD sufferers, including myself, need the dawn to tell our bodies that it is time to wake up and hence have difficulty waking up during the winter. We can also have difficulty staying awake during the day as, even though we may have had eight hours as recommended, our bodies are still convinced that we were woken up in the middle of the night.

Granted, the above problems can be worked around with a dawn simulator, but that does not excuse adopting a time system that would trigger new cases of SAD and/or worsen existing ones. The existence of a treatment for any given illness does not make it ethically acceptable to adopt an avoidable practise which will trigger that illness, and SAD is no exception.

"Melatonin is produced as it gets dark, making us feel sleepy. At dawn, as the light increases, melatonin production falls and we start to wake up. We find it difficult to wake up on dark mornings because our melatonin levels are still high."From: http://www.lumie.com/sad.htm

Other information: http://www.solar-components.com/dawnsim.htm

(Please sign your posts on Talk pages using " ~ ") But what do you disagree with? It says "some campaigners" and it says the number of cases of SAD would be reduced. Not you, perhaps, but some. Paul Beardsell 01:13, 19 Feb 2005 (UTC)

Saving/savings and such confusion
I suspect that hyphenating the title would make it more obvious as to what everything means; "daylight-saving time". porges 09:57, Mar 21, 2005 (UTC)

Sir Sandford Fleming
Does the paragraph on Sir Sandford Fleming belong in this article? I don't think so. He was involved in the creation of "standard time", i.e., time zones, but he didn't have anything to do with daylight saving time. Indefatigable 23:40, 25 Mar 2005 (UTC)

DST Errata?
What technically applies to bars and television schedules?

For instance in the fall, what do clocks jump to when it turns 2am? Do they go to 1am?, or do the clocks go from 2:59 to 2:00? What happens to broadcasts for this extra hour (besides the pragmatic answer of "infomercials"). What about bars? They variously seem to stay open an extra hour, lending credence to the former conclusion that clocks go from 1:59am to 1:00am, then resume normal progression.


 * In the UK, they genrally just schedule an extra hour/one hour less of programming. Most networks find this relatively easy to do as they are showing recorded programmes/variable length fillers overnight anyway. This spring, BBC1 just scheduled an extra hour of BBC News 24 after programmes finished, ITV1 had an extra hour of its tedious phone-in quiz show before the Australian Grand Prix. BBC2 started its recorded educational strand Learning Zone at 2:00 BST.
 * In past years some broadcatsers (that use them) have had trouble with their on-screen clocks - I remember one autumn BBC News 24 went without a clock for the repeated hour. I've also seen it appear onscreen with the incorrect time. Sometimes the teletext systems on various channels take a while to be updated with the correct time (though the BBC are usually pretty accurate with this too). This spring, Sky News, who almost always come back from a break at around x:58, put their clock back during the ad break before the change and therefore showed 1:58 when it was actually 0:58 GMT still. I've read somewhere on the internet that the BBC reported problems with its teletext service Ceefax for most of the Sunday this spring.
 * In TV guides the programmes are listed as normal until the changeover then they usually put GMT or BST in brackets to clarify. Videoplus numbers are usually printed to assume you won't change your VCR's clock until 6:00 the following morning (when listings end and begin again in the next day's page), and in TV guides they print a line explaining this.
 * Sometimes the changeover causes screwy data on the EPGs of satellite and cable systems. While the software itself works fine, the data it is provided with can be erronous. In autumn you often find channels have an hour's worth of programmes missing from the EPG and the EPG treats it as a channel closedown, or extend the length of the previous show by an hour. In spring this is not so much of a problem.
 * Lastly, because the USA changes its clocks a week later than Europe, EPG data for CNN has been out by an hour for just that one week for at least the past two years. On March 26, 2006 Wolf Blitzer introduced Late Edition by saying it was 4pm in London when it was actually 5pm.
 * --Lee Stanley 13:25, 5 April 2006 (UTC)

What happens in the case of the jump in spring, from 02:00 to 03:00? Do the clocks go from 01:59 to 03:00? As interesting as the thought exercise is, I had much better things to do than staring at a clock to figure this out. Also, I didn't realise it was DST in order to look (I noticed my alarm clock was an hour and 10 minutes behind my computer clock, instead of just 10 minutes).

Is there a "universal time" such that no time zones or DST effects occur? Something like computers do with "Seconds Elapsed since 1970". I can see such a thing being extremely critical in time sensitive calculations such as astronomy. I realise astronomers usually don't care about to-the-second accuracy, but to-the-hour accuracy makes more sense, and in the context of DST, that's precisely where the inaccuracies occur. This is illustrated by me asking what happened 48 hours ago at 1am on Month 3rd, and it just became DST on Month 2nd. I probably mean an absolute 48 hours ago, which would be 1am of Month 1st, not at 12am of Month 1st. If I were simply running calculations based on a clock, not realising or figuring in for DST, this accuracy would crop up (I'd be determining what happened 49 hours ago, not 48 as required). However, this error does cancel out if the time interval crosses the boundary from DST to Standard again. There's also some question of what kinds of errors occur when times involved fall right on these boundaries, particularly when the boundary points are at the ends of the time interval. It almost seems like the sort of ambiguity that occurs when a programmer has to make an arbitrary decision about something.

Have DST to Standard time boundaries every caused any actual problems in the real world, besides people not getting enough sleep and getting into car accidents or not doing well at work?

As far as traffic safety goes, personally, I'd come to the knee-jerk conclusion that night driving is safer than daytime. My rationale is very simple, so simple you'd say "Well, why didn't I think of that?" or the ever-perrenial "I could have thought of that."

Rationale: There's less traffic on the road at night, leading to less vehicle-vehicle collisions. This is especially true in less populated areas, but also somewhat applies in large cities as well. Of course, this neglects the problems of drowsy drivers running into more stationary objects, particularly by the ever-present collision spike around 02:15, when the drunks are kicked out of the bars (whether or not they're fit to drive) by law. Of course, if you're a night-owl like me, night driving doesn't pose much of a problem. Of course, gas being as pricy as it is now, I don't even do much driving anymore, when I can help it. JD 09:07, 3 Apr 2005 (UTC)


 * Daylight Saving Time at WebExhibits and About Daylight Saving Time address some of your questions.


 * The "universal time" without time zones or DST is indeed Universal Time, also known as Greenwich Mean Time, more particularly Coordinated Universal Time. But the latter does have leap seconds that seem to interrupt the normal flow of clock time having only 60 seconds per minute, due to Earth's slowing rotation (23:59:59 &rarr; 23:59:60 &rarr; 00:00:00 UTC). &mdash; Joe Kress 00:02, Apr 4, 2005 (UTC)

I need to research this, but my understanding is that in the US, the time shifts from 0200 to 0300 in the spring, and from 0300 to 0200, rather than 0200 to 0100 in the fall. The rationale has to do with bar closing times of 0200. The idea is to not accidentally allow bars to serve alcohol an extra hour in the fall. Sschlimgen 19:02, 29 March 2006 (UTC)


 * The law (15USC260a) is ambiguous. It states: "During the period commencing at 2 o'clock antemeridian on the first Sunday of April of each year and ending at 2 o'clock antemeridian on the last Sunday of October of each year, the standard time of each zone ... shall be advanced one hour and such time as so advanced shall ... be the standard time of such zone during such period." Neither 2 a.m. is identified as being standard time or daylight saving time. The law confuses the issue by referring to both the standard time and the advanced time as "standard time", at least for the purposes of other sections of the law.


 * The NIST actually distributes time in the United States via telephone, radio, and the internet, including whether DST is in effect. But because the changeover occurs at 2 a.m. in each successive zone, it takes six hours to fully change all zones from Eastern (UTC-5) to Aleutian (UST-10) (the other zones, Atlantic, Hawaiia, Samoa, and Chamorro, do not observe DST). To accommodate this duration the DST codes (2.9 MB pdf) transmitted by WWV, WWVB, and the Internet only identify the UTC day during which the change occurs, a period of 24 hours from 0000 UTC to 2400 UTC, not the time of day.


 * The Department of Transportation issues semiannual news statements that DST begins or ends at "2 a.m." without further clarification. So that leaves only the WebExhibits page, which is linked via the NIST government site itself, giving it some authority. It states: "In spring, clocks spring forward from 1:59 a.m. to 3:00 a.m.; in fall, clocks fall back from 1:59 a.m. to 1:00 a.m." Thus 2 a.m. is the local time when the change occurs, stated in terms of the time immediately before the change, standard time in spring and daylight saving time in autumn.


 * Bar closing times are regulated by the states and their administrative subdivisions, not by the United States government, so although those times were probably considered during congressional debate, the federal government could not set or influence those times itself. Nevertheless, the WebExhibits page states "The official answer is that the bars do not close at 2:00 a.m., but actually at 1:59 a.m. So, they are already closed when the time changes from Daylight Saving Time into Standard Time." without giving its source. I'm sure it varies depending on the state, county, or city. — Joe Kress 07:33, 31 March 2006 (UTC)

Queensland
Queensland did in fact experiment with DST, for 1 or possibly 2 years, in the late 1960s or early 1970s. I know because I lived there at the time and it was very topical. The then Premier Sir Joh Bjelke-Petersen decided not to repeat it after then. The story goes that his political supporters, a large proportion of whom were rural dwellers, did not like DST because "the cows get confused and don't produce enough milk", or "the extra sunshine fades the curtains". These are no doubt apocryphal, but still say something about the kind of people we're dealing with here. Queensland has therefore been out of step with the rest of the eastern seabord for 35 years (some would say forever). JackofOz 04:43, 11 May 2005 (UTC)

I lived in Queensland at the time, and thought that it meant I'd get an extra hour to lie in bed of a morning and read. Boy, was I wrong!

The reason it was dropped wasn't political but geographical. Queensland is one of the more decentralised States, and consequently a large percentage of the population lives north and west of the capital city of Brisbane, which is at the extreme south east corner of the State. With the Tropic of Capricorn only a few hundred kilometres north of Brisbane, a large amount of the State is in the tropics where the benefits of Daylight Saving are minimal. The coastline trends north-westerly, exacerbating the problem the further north one goes. Residents of Mount Isa, for example, found that in summer they were having to get up before dark, and schoolchildren were walking home during the hottest part of the day. There was little benefit in it for a great many Queenslanders, and rather than divide the State into two time zones, the scheme was dropped. It must be remembered that Tasmania, the southernmost State, begins DST earlier and ends later than the mainland States, and that the permanent difference in time zones between (say) Victoria and South Australia causes no problems. Pete 09:06, 23 May 2005 (UTC)

Queensland had a second trial of DST, in the late 1980's/early 1990's, with similar problems to what Pete has mentioned. I seem to recall that a referendum was then held, with the "No" vote winning. Johnmc 13:57, 5 February 2006 (UTC)

DST in Winter
I've long thought that in a hot and sunny country like Australia, we should have DST, but rather than doing it in summer, we should do it in winter instead. Australia is already way too sunny, as evidenced by the highest rate of skin cancers in the world. We simply don't need any more daylight in our lives in summer, we have too much already. But in winter we could definitely do with some more daylight at the end of the day, whereas currently we tend to go home in at best fading light, or more usually darkness. Yes, it would mean we'd be getting up in darkness, but that's true for most people anyway so there's no loss there. I've been on this particular soapbox for at least 30 years, but so far our governments have failed to heed my brilliant advice. JackofOz 04:43, 11 May 2005 (UTC)


 * But who wants extra daylight in winter anyway, I'm from Victoria and even in the late afternoon during winter it is not exactly the kind of the weather I want to be outside in anyway. The offset of daylight it provides is useful, dinner on the patio at dusk, and then a nice summer evening walk and a touch of fishing. that's what summer is all about in Australia. Nath85 14:47, 27 October 2006 (UTC)

DST all year round

 * The only advantage I can see to having DST all year round is, rather than adjusting everyone's perception of time(9-to-5 is now 8-to-4), it adjusts the time zone to get rid of the phsychological aspect 4.232.102.207 20:15, 22 July 2005 (UTC)
 * I know, it's pretty amazing that nothing actually happens to the sun or the earth's rotation. All we're doing is some renumbering. CoolGuy 18:52, 7 August 2005 (UTC)

Start and end dates

 * Doesn't it seem a bit funny that the sunrise/set times in late October match up with those in mid-February better than in early April? WHy didn't they change DST so it would last from Oct-mid-Feb?

Also, DST is in effect for most of the year (7 months: Apr-May-Jun-Jul-Aug-Sept-Oct) compared to (5 mtohs: Nov-Dec-Jan-Feb-Mar). Maybe it would make more sense if we hat Winter Time and Standard Time? This would also get rid of the confusion about LST meaning Local Standard Time and Local Summer time as well.

Sunrise times in late October under DST match up with sunrise times in January under standard time and would match up with sunrise times in early March under DST. It seems as if we are using a sliding system in which the clocks are shoved ahead when the sunrise times by the clock are becoming too early (early April sunrise times under standard time are similar to those in June under DST) and the clocks are retarded when sunrise time is becoming too late. It would make more sense to balance the start and end dates, preferably at the equinoxes. In other words daylight saving time should start in late March and end in late September.

Recent US changes to DST
Shouldn't there be a mention of the (proposed?) changes to DST in the USA? They're talking about extending it by four weeks, or maybe they've already passed the laws.


 * It's already there: Daylight saving time, 5th through 7th paragraphs of the section. Indefatigable 01:22, 11 August 2005 (UTC)

The Canadian province of Ontario announced today that it will follow the U.S. changes in 2007. http://www.newswire.ca/en/releases/archive/October2005/20/c3858.html Rkahle 00:10, 21 October 2005 (UTC)

Moved some references of Canadian province changes to the time in Canada page. —Preceding unsigned comment added by 206.47.249.251 (talk • contribs)

Material related to start / stop dates of North America are subject to frequent updates as the countries that observe DST make the changes to their laws to get back in sync with the US for 2007. Jon 16:21, 16 June 2006 (UTC)

Offsite link
Link #4 is no longer valid, but a replacement may be nice....


 * The fourth site from the top under External links (the EU directive) is still valid. &mdash; Joe Kress 17:32, August 19, 2005 (UTC)


 * I think the anon was referring to the fourth unlabelled link in the article, which displays as "[4]". That was (until I removed it) http://www.denverpost.com/opinion/ci_2889827 - which is indeed invalid - but there's another link right next to it which is presumably similar. Since all we have is a number, not a real reference, finding the article if it's just moved may be hard. - IMSoP 20:02, 19 August 2005 (UTC)


 * Many newspapers archive articles into an area that only subscribers can access, making it inappropriate as a Wikipedia link. A poor substitute would be an equivalent New York Times article. They allow free access to the archived article's headline, dateline, and page, which is sufficient to allow someone to access the text of the article in their local library, unless they are willing to pay for the text online. &mdash; Joe Kress 21:23, August 19, 2005 (UTC)

Battery-powered smoke detectors
Aren't most modern fire alarms and smoke detectors wired to the electric wire of the house (like the lights), as opposed to using invidual batteries? I've never changed my house's smoke detector batteries, nor do I even think there's any! --Menchi 20:41, 29 August 2005 (UTC)


 * I've never seen a mains-powered smoke detector in a house! :) porges 02:15, August 30, 2005 (UTC)


 * Both battery and mains-powered smoke detectors are used. They use different methods to detect smoke and indeed each is better at detecting smoke from a specific ignition source than is the other. For best smoke detection, both types should be used. &mdash; Joe Kress 03:35, August 30, 2005 (UTC)


 * Dual-power smoke detectors are common in the US. Such detectors utilize house wiring at 120V AC as their primary power source and a 9V DC battery as backup in the event of a power outage. man1ey 10:40, April 21, 2006 (EST)


 * See about batteries and mains operated detectors. Different type of power supply doesn't mean different detection system. Jclerman 15:06, 21 April 2006 (UTC)


 * See and  to learn about the two types of smoke detectors (optical and ionization) which can use either battery or mains power. Jclerman 15:10, 21 April 2006 (UTC)


 * Forgive my ignorance, but what the hell does this have to do with DST? Joe 1987 02:37, 30 April 2006 (UTC)
 * Precisely, somebody had a hell of a time trying to find the batteries to replace them, as recommended, the day he/she changed the clocks to DST. Then somebody tried to explain why there were detectors with and without batteries, etc. Jclerman 02:51, 30 April 2006 (UTC)

Where is the key information?
I just visited this article wanting to know when Daylight Saving Time is in the Eastern time zone, and I had to scroll down quite a ways in the article to find out. And the article on Eastern Daylight Time is even less helpful. Perhaps someone with time on his hands could create a table for quick reference as to when DST begins and ends for each time zone/state? Just a thought. --zenohockey 17:06, 3 October 2005 (UTC)

Japan etc
The fact that Japan does not observe DST has been in and out of the article a couple of times. While I agree that a separate section in this article on Japan is too much, I think one should be able to find the fact in Wikipedia. Perhaps in a table, as suggested in the previous talk entry by zenohockey (but not limited to USA)?--Niels Ø 19:00, 11 November 2005 (UTC)


 * Wikipedia is not an endless compendium of every fact imaginable. If you want to put together a list of countries that observe DST and those that don't, they might be able to exist as their own articles, but I question their usefulness.  An article about DST should tell us what DST is, its history, purpose, changes over time, challenges to it, and a sampling of how various groups practice it.  An article about currency wouldn't need to list what currency every country in the world uses it, but a small sampling is appropriate.  The other information has its place elsewhere. Peyna 21:16, 11 November 2005 (UTC)


 * Time zone already lists all countries and whether they observe DST (via one or two asterisks). Countries that don't observe DST, like Japan, don't have an asterisk. &mdash; Joe Kress 08:27, 12 November 2005 (UTC)


 * Sorry I guess I missed this section when creating the one below. I agree with Joe Kress and Penya.  Use and history of DST is the driving force behind inclusion in this article; note that the US has a large section because its DST implementation is complex (Indiana is noted for its unusual [perhaps perverse] observation, and Hawaii and Arizona are noted for their non-observance in a country that otherwise uses DST).  There may be other geographical entities whose system warrants a similarly large section, but countries that don't observe DST, such as Japan, don't need to be mentioned.  However, it might be good to indicate more prominently that observation of DST is listed in the time zone article. Fsiler 08:40, 12 November 2005 (UTC)

Policy on usage section
The point of this article should not be to list every country; rather, it should be to list conventions or history where applicable. My regards to the person who added Japan, but I don't think it's terribly useful just to note that Japan doesn't use DST. It'd be much more worthwhile to note if they had experimented with it and rejected it, for example. Fsiler 12:43, 31 October 2005 (UTC)

Intro
Someone changed the intro to say "North American" instead of "U.S." term, which is fine, except that I'm pretty sure in Mexico its referred to as "summer timetable," or "Horario de Verano" in spanish. So "U.S. and Canadian" term would be more accurate. Perhaps the intro could just be rewritten to read something like the following in order to avoid the problem all together, then there can be a section about what people where call it. I'll let this sit here either until it gathers some comments or is ignored for a few days and then move it out to the main page if there is no problem.

"Daylight saving time (DST) (also known as, summer time, summer timetable, summer schedule) is the term for a system intended to 'save' daylight. In most cases, the official time is adjusted forward one hour from its official standard time throughout the spring and summer months. The purpose is to provide a better match between the hours of daylight and the active hours of work and school. DST is most commonly used in temperate regions, due to the considerable variation in the amount of daylight versus darkness between the seasons in those regions."

Peyna 15:21, 20 November 2005 (UTC)

Table of countries that use it, when and how
I think it would be extremely handy to have a table of information containing a list of when a country begins its DST, when it leaves it, how large the offset is, and when it will change in the future if relevant (this has particular relevance to the United States at the moment).

I can see the argument that it doesn't belong on a page discussing the history and rationale behind DST, but it is certainly the case that it would be incredibly useful. I'd even broach the theory that at least 50% of the people who visit the Daylight saving time page are looking for just such information. I'd be happy to fire one up of no one objects. Markkawika 06:23, 16 December 2005 (UTC)


 * Maybe that would be appropriate for a subpage, so that it doesn't clutter the main page up? I think that's most people's concern. Peyna 14:15, 16 December 2005 (UTC)


 * You are basically proposing to take a copy of the Zoneinfo database and put it in as a wikipedia article. If you haven't read a recent version of the zoneinfo files, I suggest you do.  They are very detailed.  If you really think this would be of value, rather than just referring people to the file elsewhere, then definitely use a subpage, not the main page.  You can get an up to date copy of the Zoneinfo file at  Stephen.frede 05:39, 4 March 2006 (UTC)

Question Regarding Origin
There's an infamous quote: "Britain was the first nation to adopt daylight saving schemes in 1908. Some people believe the pragmatically minded British did it to make economy on candles." TASS, Moscow, is the quote incorrect, or the origin paragraph?


 * The origin paragraph is correct—Tass in wrong. I am surprised that Greenwich Mean Time would have such an erroneous quote on its web page. Although Willet proposed DST in 1907, Britain did not adopted it until World War I. — Joe Kress 07:45, 9 March 2006 (UTC)

Microsoft botchup
MS really botched up their DST for the Melbourne 2006 Commonwealth Games. I just can't understand why they added a new TZ instead of altering the existing one! - Ta bu shi da yu 13:42, 9 March 2006 (UTC)

Table?
Should we add a table as to when DST starts and ends around the world, and record any historical changes that were made (ie Sydney Olympic Games & 2006 Melbourne Commonwealth Games)? - Ta bu shi da yu 13:46, 9 March 2006 (UTC)

Computers
The section on "Computer systems" smells slightly of advocacy. It knocks Microsoft Windows for not being flexible enough to handle rules changes, while praising Unix (a competing operating system) and Java (a programming language and "tool library").

I happen to agree with this assessment - being a BIG FAN of Java - but shouldn't all advocacy be attributed to a Person or other source? --Uncle Ed 16:11, 14 March 2006 (UTC)


 * I wrote the original section and I've re-read the material and I don't think there is any advocacy. There are details about each OS and the section does mention one of the problems of the MS approach, but that is all factual (and extremely important to people using MS - the US rule change next year will cause far more problems than the Aus change did this year).  I really don't think this reads as advocacy at all. Stephen.frede 00:24, 1 April 2006 (UTC)

..The first thing I noticed when reading this article *was* the advocacy stated above. The only thing that needed to be said was that different operating systems and applications handle DST in different ways, depending on how that O/S or application was written. UNIX/Linux can, in fact, be wrong if the hardware is capable of making adjustments to the clock to allow for DST.71.244.163.156 10:07, 1 April 2006 (UTC)


 * The current version does seem incomplete, in that there is no discussion of possible problems with the Unix and Java approach. Other situations where problems may arise are in mixed environments, e.g. networks of Unix and Windows machines, or a dual-boot machine.
 * I don't agree that there is undue advocacy in the current version. After all, there is a problem with the Windows approach, and I think it is more useful to explain this than to just say how it works and expect readers to figure out the problems for themselves. But I agree that external sources should be given, and problems with other software should be discussed.
 * By the way, I noticed this year that Windows (XP SP2) changed back to Standard Time an hour early here in New Zealand, i.e. from 2am DT -> 1am ST, not 3am DT -> 2am ST as it should. In contrast, my Debian GNU/Linux system worked fine. Has anyone noticed whether this problem occurs in other time zones (e.g. in Australia)? -- Avenue 11:52, 1 April 2006 (UTC)

We could move Britain to CET, or...
Has anyone thought that Britain switching to CET could be done better by moving Andorra, Belgium, France, Luxembourg, Monaco, the Netherlands and Spain onto UTC as they all fall roughly between 7°30'W and 7°30'E...? Maybe? Shall we discuss this (it is the Discussion page)? Gee Eight 19.49 WET (Western European Time) 16 March 2006

World War II
I believe I read somewhere that during World War II, for a brief period of time they implimented double daylight savings time to help with the war effort. The clocks were turned ahead two hours.
 * If this is true, it would be great to add to the article. —Preceding unsigned comment added by 141.151.164.18 (talk • contribs)
 * I believe it is true, and was known as 'double-daft time'. jazzle 22:48, 18 April 2006 (UTC)

Programmers?
The article says that:

No formal studies have been performed, but an enormous amount of time has been spent by software developers to deal with the fact that 2400 hours past 2pm is not necessarily 2pm 100 days later.

This is blatantly misleading. As any programmer should know, DST has been a part of standard libraries for a very long time, and the normal programmer does not have to worry about it at all. --69.221.228.91 14:09, 2 April 2006 (UTC)


 * It's true that the applications programmer never worries about DST, but the systems programmers do. In fact, Microsoft's solution to the one time extenstion of daylight savings time in Austriala for the winter games and the switch in Indiana both required some work by systems admins on the effected systems. (Install a patch for Australlia before the games and then uninstall it afterwords. Those your clock settings from Indiana to Eastern prior to start of DST for those that switched. For those counties that changed timezone in Indiana from Eastern to Central, switch the clock settings from Indiana to Central after the start of the DST. ) Jon 16:17, 16 June 2006 (UTC)

Criticism Section
... needs a rewrite - it is poor English, and is certainly US English biased.


 * I agree, I have read a number of sections of the article and considering this is already a complicated topic, this article certainly doesn't help to make it easier to understand. For example in the section about Arizona it gives the reason for not opbserving DST as something to do with air-conditioning, I mean, wtf? Joe 1987 02:35, 30 April 2006 (UTC)


 * Both Phoenix and Tucson frequently have highs above 100 F during the summer, and occansionaly above 110 F. This is in the ballpark of 40 C. Jon 16:11, 16 June 2006 (UTC)

Alaska: Explanation for opposition
The article states:

"currently observes DST, however, there is a petition drive to place a question on state ballots in 2008 to discontinue DST in the state. This is driven by concern for safety in the morning, when it will be dark for several hours due to the extremely short winter days at such latitudes"

This needs clarification or explanation. On the face of it, whether or not Alaska observes DST in the summer will have no effect on the safety of driving in the morning in the extremely short winter days. Ordinary Person 08:14, 12 May 2006 (UTC)


 * Actually, since the Wiki is not a crystal ball, I'm going to remove the Alaska section entirely for now. Until petitions are submited, it doesn't belong here. Jon 15:45, 16 June 2006 (UTC)

very minor edits
I changed the capitalisation of the word Lady, as it is clear from the context that Lord Balfour was talking about a Lady, not a lady. If that makes any sense.--Blah.blah.blah 19:07, 6 June 2006 (UTC)

POV related edits
I've pulled most of the POV statements from individal states; no need to duplicate portions of pro/con arguments from those sections for each state. I've also changed the section of the name; the wiki is supposed to report what name(s) are used not say one choice is superior or inferior. I've also cut down Indiana in size since it now observes DST. Finally, I've added requests to cite a few sources. Jon 16:04, 16 June 2006 (UTC)