Daylight Saving Time Explained


Every year some countries move their clocks
forward in the spring only to move them back in the autumn.
To the vast majority of the world who doesn’t participate in this odd clock fiddling – it
seems a baffling thing to do. So what’s the reason behind it?
The original idea, proposed by George Hudson, was to give people more sunlight in the summer.
Of course, it’s important to note that changing a clock doesn’t actually make more sunlight
– that’s not how physics works. But, by moving the clocks forward an hour,
compared to all other human activity, the sun will seem to both rise and set later.
The time when the clocks are moved forward is called Daylight Saving Time and the rest
of the year is called Standard Time. This switch effectively gives people more
time to enjoy the sunshine and nice summer weather after work. Hudson, in particular,
wanted more sunlight so he could spend more time adding to his insect collection.
When winter is coming the clocks move back, presumably because people won’t want to
go outside anymore. But, winter doesn’t have this affect on
everyone. If you live in a tropical place like Hawaii,
you don’t really have to worry about seasons because they pretty much don’t happen.
Every day, all year is sunny and beautiful so christmas is just as good of a day to hit
the beach as any other. As so, Hawaii is one of two states in the Union that ignore daylight
saving time. But, the further you travel from the equator
in either direction the more the seasons assert themselves and you get colder and darker winters,
making summer time much more valuable to the locals. So it’s no surprise that the further
a country is from the equator the more likely it uses daylight saving time.
Hudson proposed his idea in Wellington in 1895 – but it wasn’t well received and
it took until 1916 for Germany to be the first country to put it into practice.
Though, the uber-industrious Germans were less concerned with catching butterflies on
a fine summer evening than they were with saving coal to feed the war machine.
The Germans thought daylight saving time would conserve energy. The reasoning goes that it
encourages people to say out later in the summer and thus use less artificial lighting.
This sounds logical, and it may have worked back in the more regimented society of a hundred
years ago, but does it still work in the modern world?
That turns out to be a surprisingly difficult question to answer.
For example, take mankind’s greatest invention: AIR CONDITIONING. The magic box of cool that
makes otherwise uninhabitable sections of the world quite tolerable places to live.
But, pumping heat out of your house isn’t cheap and turning on one air conditioner is
the same as running dozens of tungsten light bulbs.
If people get more sunshine, but don’t use it to go outside then Daylight Saving Time
might actually cost electricity, not save it.
This is particularly true in a place like Phoenix: where the average summer high is
107 degrees and the record is 122. If you suggest to an Arizonian to change their
clocks in the summer to get more sunshine, they laugh in your face. More sun and higher
electricity bills are not what they want which is why Arizona is the second state that never
changes their clocks. Another problem when trying to study daylight
saving time is rapid changes in technology and electrical use.
And as technology gets better and better and better more electricity is dedicated to things
that aren’t light bulbs. And the lure of a hot, sweaty, mosquito-filled
day outside is less appealing than technological entertainments and climate-controlled comfort
inside. Also the horrifically energy in-efficient
tungsten light bulbs that have remained unchanged for a century are giving way to CFLs and LEDs
– greatly reducing the amount of energy required to light a room.
So, even assuming that DST is effective, it’s probably less effective with every with every
passing year. The bottom line is while some studies say
DST costs more electricity and others say it saves electricity, the one thing they agree
on is the effect size: not 20% or 10% but 1% or less, which, in the United States, works
out to be about $4 per household. $4 saved or spent on electricity over an entire
year is not really a huge deal either way. So the question now becomes is the hassle
of switching the clocks twice a year worth it?
The most obvious trouble comes from sleep depravation – an already common problem
in the western world that DST makes measurably worse.
With time-tracking software we can actually see that people are less productive the week
after the clock changes. This comes with huge associated costs.
To make things worse, most countries take away that hour of sleep on a Monday morning.
Sleep depravation can lead to heart attacks and suicides and the Daylight Saving Time
Monday has a higher than normal spike in both. Other troubles come from scheduling meetings
across time zones. Let’s say that your trying to plan a three-way
conference between New York, London and Sydney – not an easy thing to do under the best
of circumstances but made extra difficult when they don’t agree on when daylight saving
time should start and end. In the spring, Sydney is 11 hours ahead of
London and New York is five hours behind. But then New York is the first to enter Daylight
Saving Time and moves its clock forward an hour. Two weeks later London does the same.
In one more week, Sydney, being on the opposite side of the world, leaves daylight saving
time and moves its clock back an hour. So in the space of three weeks New York is
five hours behind London, then four hours and then five hours again. And Sydney is either
11, 10 or 9 nine hours from London and 16, 15 or 14 hours from New York.
And this whole crazy thing happens again in reverse six months later.
Back in the dark ages, this might not have mattered so much but in the modern, interconnected
world planning international meetings happens 1,000s and 1,000s of times daily – shifting
and inconsistent time zones isn’t doing netizens any favors.
And, to make matters worse, countries aren’t even consistent about daylight saving time
within their own borders. Brazil has daylight saving time, but only
if you live in the south. Canada has it too, but not Saskatchewan. Most of Oz does DST,
but not Western Australia, The Northern Territory or Queensland.
And, of course, the United States does have DST, unless you live in Puerto Rico, the Virgin
Islands, American Samoa, Guam, the Northern Marianas Islands or, as mentioned before Hawaii
and Arizona. But Arizona isn’t even consistent within
itself. While Arizona ignores DST, the Navaho Nation
inside of Arizona follows it. Inside of the Navaho Nation is the Hopi Reservation
which, like Arizona, ignores daylight saving time.
Going deeper, inside of the Hopi Reservation is another part of the Navaho Nation which
does follow daylight saving time. And finally there is also part of the Hopi
Reservation elsewhere in the Navaho Nation which doesn’t.
So driving across this hundred-mile stretch would technically necessitate seven clock
changes which is insane. While this is an unusual local oddity here
is a map showing the different daylight saving and time zone rules in all their complicated
glory – it’s a huge mess and constantly needs updating as countries change their laws.
Which is why it shouldn’t be surprising that even our digital gadgets can’t keep
the time straight occasionally. So to review: daylight saving time gives more
sunlight in the summer after work, which, depending on where you live might be an advantage
– or not. And it may (or may not) save electricity but
one thing is for sure, it’s guaranteed to make something that should be simple, keeping
track of time, quite complicated – which is why when it comes time to change the clocks
is always a debate about whether or not we should.�

Comments 100

  • The real reason Daylights Savings (and Time Zones) were instituted was for farmers and travel. While this video makes the current system out to be a nightmare, it was actually 100x worse before. Because each local town, county and state would have their own official times. You wouldn't just be changing your clock going from country to country, but just town to town. Yes, we could update the system now to something better. But the question wouldn't be how it effects citizens living in a big city. The question is how it would effect the farmers and people in rural areas.

  • It actually started during world war 1when Us expanded 1hr in order to utilise more and more daylight..Aterwards,it was expanded by British during world war 2 by forwarding their clock to 2 hrs known as double summer time..

  • What I like is when he showing the pic which represents Syndey, it's upside down 😂😂😂

  • YEAR ROUND DAYLIGHTS SAVINGS TIME! We all get to enjoy the evening sun without changing the time.

  • You make good points

  • In Uruguay we used to have DST until 2015.

  • dude i lived in AZ for like a year and didn't know they don't use DST =S

  • HOLY SHIT THE PHOTO AT 3:49 KILLED ME

  • The whole world should shift to UTC 00:00. It may mean people in sydney will get out of bed at 9:00pm, noon will be at 3:00am and work will finish at 8:am but these are just numbers, they can adjust.

    Edit: The work day would start at 12:00am though making time sheet calcultions much easier.

  • Honestly, more sunlight in the summer just seems like a weird thing to want. Where I live with DST, it's still daylight in the summer until well after 9 PM. In the winter, it was full dark by the time I got home from school. Neither of those things feels natural.

  • Fuck daylight savings time

  • But you are missing the most important point. Why is there so much pressure to keep it.

    The idea is that people get out of work and, as it is still daytime, they go to the stores to further increase the already-too-high consummism.

  • Why can't people handle an hour to or from?

  • So the EU is looking to rid of DST but Ireland is looking to veto the move as northern Ireland as part of the UK won't get rid of DST. this would result in two times zones on the on the same island

  • 4:35 I might want to do that and see others also do it

  • What if we had an international time zone, and people just got used to midnight being at 14:00

  • 0:57 Except Hawaii actually rains all the time but it's okay because it's happy rain.

  • Don't you mean in the winter and not summer

  • There's something about how we measure time that nobody has a problem with but doesn't make sense

    Time switches between AM & PM at 12:00
    Like, it goes
    11:58 pm . . . 11:59 pm . . . 12:00 am, ok it's tomorrow

    Why not make the switch happen at 1:00?
    Would make sense for the beginning of the day to be 1:00, or for it to become afternoon at 1:00

  • Us in Nevada hotter than Pheonix and still have daylight savings

  • In BC, Canada there also are a few cities that don't use daylight savings time. I lived in one of them throughout my childhood and teen years. I didn't even know it existed until I was like 16

  • It may seem later but it is earlier.😂

  • @4:56 "Most of Oz has daylight savings time" except 75% of the landmass.

  • DST should just be the standard time all year round.

  • Ach du lieber! The Germans… so let me get this straight. A guy comes up with a whack idea for…reasons; the world says…meh; Germany does a double-take and thinks, Winning, because…World Domination. Sooooo, fast forward, the Master Race thang doesn't work out for…more reasons, and the world gives Germany a spanking and sends them to their room; the Motherland says, "make that two rooms and everybody in this room is grounded". Sooooo. Faster forward, the world says, "Fuckin aye, aye? Remember that whack idea? Yeah, but shut up, you're not the boss of me, well, neither are you, and you can't make me, I know you are but what am I and…" "Ok, perfect!" *holds up indecipherable map and says, "There, you can't stop Progress!" *everyone applauds… Someone somewhere says, "I have another idea!" *world holds it's breath "Let's pretend we're all friends and call it, oh I don't know, how about European Union?" "But what about the rules?", someone asks. "We'll work it out, don't worry about. Ready? Go!" …meanwhile, In Germany, someone says, "Hey, I was just thinking 💭 remember that World Domination thang…?"

  • fuck daylight saving time.

  • I don’t like George Hudson…

  • DST was a mistake

  • only reason why i like daylight saving time:

    when you turn back the clock 1 hour back for that just 1 day.

  • 😍 love those jugs @ 1:29🍺 :p

  • Disappointing bias throughout your video.

  • You know a CGP Grey video is old when there's no background music or stick figures

  • Who the hell is dumb enough to argue for dst?

  • Brazil doesn't switch anymore 🙁

  • 5:23 triple dst enclave!

  • so much hassle if you want more time enjoying in summer just fucking wake up early

  • When I moved out of Arizona, boy did I have a hard time grasping DST. Many late or early days to work.

  • It’s literally an hour, it’s a bit dramatic for ppl to complain about sleep lol. Just take some melatonin. also for farmers it’s very, very important.

  • 4:00 Grey liked. The joke before it was cool!

  • an hour is nothing its like saying 30 minutes is a long lunch, it's not.

  • So funny.

  • Observing some productivity loss at the transition doesn't tell us anything about the effect of having light at different times of day (by our schedule) during the other fifty weeks of the year.

  • We DEFINITELY should have DOUBLE Daylight Saving Time in May, June, and July.

  • LIAR!!! The Fall back is also ON A SUNDAY.

  • DST lasts MUCH LONGER than 6 MONTHS, DUMBASS!!!

  • Is it just me or do us only watch these videos to get sleepy at night to go to sleep

  • Westen astralia dosent do it! And I think its weird!

  • White people problems

  • By the way, timezones makes no sense at all.
    If we didn't use timezones, I could say "15:30" in any part of the world and the entire world would understand it.
    In some places it would be night and in others it would be day. Simple.
    But with timezones you make a ridiculous amount of math only to name the noon 12:00 everywhere.
    Wich makes no sense because the planet is round and spinning around the sun and itself.

  • Of course you could just be russia and keep daylight savings time on even after it should've been finished.

  • Btw again "DST" in my language means "sexual transmission disease".

  • May June July August September New York is only 14 hours in the northern summer southern winter
    in Spring and autumn 15 hours Southern summer northern winter 16 hours So it is a good thing
    in May June July August September

  • And also because of WWI

  • Why would anyone actually believe this lol

  • I don’t. Have daylight savings and I Aussie boi
    Edit: oh wait I’m Western Heheh………..

  • Can we just rename Standard Time to Daylight Wasting Time already?

  • What is more mathematically accurate to the Earth's rotation around the sun? Whatever it is. Let's go with that. Cause that's what we're all taught this shit is based around or do we throw out the whole lesson?

  • Well, in a few years, I think, we will have gotten rid of it again

  • 2:20 thanks, I just wanted to google it^^

    3:57 I love, that sidney is upside down^^

  • That 100 mi line, if stretched to just past Arizona’s borders, would add another 3 changes

  • Brazil is so strange
    It's like half of the states don't have daylight saving time

  • I think it's best to make the time exactly 12pm wherever you are when the sun is at its highest point in the state where you are. If everyone on the planet would do this we'd all be linear and everything would make sense. Obviously the polar caps have an issue but easily resolvable. The longitude where Alaska or Greenland is located just needs to follow what the timezone is for the locations below them in the same longitude. So in other words, You go along the Equator and set the times there, and then the states and regions above or below those marked times round their time to the nearest hour based on the time at the equator. A 360 degree turn of 24 hours.
    Don't get me started on 12am,pm vs military 24 hour time usage. Our clocks should be 360 hour times not 24.

  • it's about having enough light for batting at cricket practice. daylight saving follows cricket season and without the longer evening light hours (stolen form the morning) there would not be enough time to get enough batting in. (an Australian)

  • Daylight saving is just stupid af

  • I hate it when im travelling and I have to adjust

  • No DST in Brazil this year!

  • It's all about government control

  • Time to eliminate this shit.

  • British Summer Time

  • The sleep depravation thing ONLY goes for places that actually use the correct timezone, which is less than you might think. Take my country, the netherlands, if we rejected daylight savings time we would in fact be TWO hours out of tune with actual biological time (as in, sun at its highest at noon), which means for us rejecting DST would increase sleep depravation quite a bit because it messes with the light/dark awake/asleep balance.

  • Time is already a complicated mess of a concept, let's do one thing to reduce the complications to scientific/philosophic only. Get rid of day light savings times

  • 3:18 U know you’re late to a video when u see these…..

  • Just just follow the rule, and enjoy your life

  • I'm Kiwi born and brought up in India. India don't need daylight saving but NZ does. We are in house arrest not just with cold but rain. Although we enjoy snow. In summer, sky is the limit. People live the life they want to. Electricity bill is halved. Spend in on fun with nature.

    So everything is not about stats. It's about life. And what's the hassle? Everything that's on internet changes the time itself and never heard of any international business dealings gone wrong because of daylight savings, if it did.. they are not businessmen.

  • Did no one notice he flipped the Sydney opera house because Australia is the upside down?

  • We should invent
    International Meeting Time (IMT) which consist of 48 hours of international day

    It is 48 so any countries would already passed a day of their 24 hours time, so nights and day are thrown away.

    You'd hear something like "Yo lets have a formal meeting at 28 o'clock IMT"

  • 4:52 "MOST" of AUS lol

  • There is ABSOLUTELY NO sleep deprivation due to DST. He’s LYING!!!!!

  • The "more people die of heart attacks" is a bit more complex than that. DST still sucks tho

  • How many of you came here after seeing pluralsight video on date and time fundamentals ?

  • Navajo nation though. Hard life there

  • The clock change in the UK happens in the early hours of a Sunday morning. At 01.00 Greenwich Mean Time (GMT) on the last Sunday in March it becomes 02.00 British Summer Time (BST) – at 02.00 on the last Sunday in October it becomes 01.00 GMT.

  • what a fukc up

  • i would say abolish it but keep the summer time. its really annoying when it gets dark at 4 pm in the winter.

  • Btw egypt does it

  • When i lived in germany as a kid. I thought day light saving time was a necessity since we never changed it back near winter time….or maybe i managed to always miss it in winder time

  • 5:41 Here China is shown it's pre-1949 timezone. Nowadays all of China uses UTC+8, and there are no daylight saving time.

  • We have DST in the winter in reverse land

  • Fu☆k day light saving time.

  • 🇦🇺👍👋🙄DAYLIGHT SAVINGS IT'S VERY GOOD

  • https://www.yang2020.com/policies/extend-daylight-savings-time-all-year/

  • Why is everyone so fixated on energy costs? The point is to have people not sleeping with the sun out and shining and so, DST makes the sun rise as close to the same time as possible. No one is golfing at 5 am, but people are still golfing at 8:30 pm. Golf courses would lose BILLIONS and fuck the economy if you ever got rid of DST.

  • Just down of Arizona is where i live, in Sonora, Mexico. I just noticed that theres daylight saving time bcs of series lmao. Arizona and Sonora have the same weather so both don't use dst.

  • So you're telling me nobody stayed in these hot places before air conditioning

  • Love the international phone call graph! As a Aussie from Western Australia I don't like daylight saving. I don't want to be doing things outside in the hottest part of the day. I'd rather it went the other way! With standard time in WA, it's getting dark about 8.30pm and still very hot (can be 35C +). Why not get up earlier and enjoy the pleasant 25C+ temp then.

  • Daylight Saving is bloody stupid. I live in Queensland Australia. This state doesn’t have this dum law. Other Aussie states unfortunately have this ludicrous Daylight Saving. I support our farmers who hate Daylight Saving more then I do, most of them hate DS.
    I have many reasons that I hate DS. To sum it up, I find Daylight Saving is so stupid, I call it Daylight Puking, cause daylight saving is so terrible it makes me sick. I’m a city person too. I agree with most farmers, this should be banned.

  • today it just happend im in Australia 🇦🇺

  • Despite its potential flaws, it makes sense giving you more daylight while awake, which long term can help with sleep.

  • I would do anything for DST to be abolished worldwide

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