Daylight Saving Time

Can man control the motion of the stars?The suggestion to save daylight makes daylight saving time an attractive proposition. If you have lived, as I have, at 60°N, you would certainly be partial towards a possibility to take some of the ample daylight going to waste as you sleep in summer and apportion it to the those dreary, dark hours in winter before and after work. Unfortunately, since Earth rotates around its own axis and around the sun at fairly constant rates and stubbornly refuses to adapt to our wishes, that is possible only with technical props such as solar power collectors, power distribution systems and artificial lighting. That is what we already do and it doesn’t really help much.

Daylight saving time, it seems, does no such thing as to change the motion of the planet or to save up daylight for a snowy day. Instead, it is the practice of setting the clocks forward one hour from standard time during the spring, summer and autumn months, and back again before winter, purportedly in order to make better use of daylight. OK, so it is supposed to be better-use-of-daylight time, not actually daylight saving time. That sounds a lot less attractive but still sensible enough. What does better use of daylight mean, then? Is more better? Is more useful better? Is more efficient better? In that case, for what purpose? How do we decide what good use of daylight is? Because apparently, we must have, and we did. In order to properly and fairly evaluate the utility of daylight saving time, it seems we must find out to what extent daylight saving time helps us make better use of daylight in the sense that we presently make good use of daylight.

Daylight Usage

People get up in the morning, work in the day and stay up late for amusements. It is the same all over the world and it doesn’t vary much with latitude. No one who doesn’t suffer from a serious condition, or is an inveterate bird watcher, gets up early for sybaritic pleasures in the wee hours, and few consistently consider it an indulgent luxury to sleep long by getting into bed as early possible, long before the sun has set. Since we have in our bodies several hormones whose levels vary with the day/night cycle, either directly through the influence of light-sensitive tissue such as our eyes, or indirectly through our inner clock, this should come as no surprise. After a billion years of evolution, we are pretty well adapted to life on earth and are able to make good use of daylight. And, oppositely, the way we are created to enjoy sunlight is pretty much the way we spontaneously do.

Now, one could argue that we no longer live a spontaneous and natural life, but subject our use of daylight to social regimes enforced by morals and clocks, most conspicuously alarm clocks. Technology allows us to live each day in a similar way during all seasons also at higher latitudes, where the length of day and night vary over the year. Fixed hours in schools and workplaces force us to, typically, get up earlier in the morning than we feel we would like to. We have learned to accept this as a good thing distinguishing the hard-working and well behaved. This situation presents an alternative notion of how we define good use of daylight. Perhaps no one knows for sure at what times we would be awake without clocks, but our instinct is clear to get up late and stay up late, and we counterbalance this with social and moral constructs to make us get out of and into bed earlier.

The Arguments for Daylight Saving Time

How does daylight saving time propose to improve on the settled scheme of daylight usage? First of all we must appreciate the fact that daylight saving time is one of these social regimes enforced by morals and clocks, which act to move our usage of daylight away from the natural or spontaneous condition. But perhaps it still represents an improvement to the earlier regime? The following advantages are proposed as reasons for the adaption of daylight saving time:

  1. Reduce energy usage, especially that of artificial lighting
  2. Improve road safety by placing commute times in the sunlit part of the day


  1. Give workers more sunlit free time after the work day
  2. Produce more military equipment before the sun sets each day

and finally

  1. Align the wake part of the day with the sunlit part of the day

I have placed these arguments in three groups, because they are within the first two groups really just variations or examples of the same two principles, whereas the third group is void. Let’s deal with it first. It contains no argument in itself, but just a placeholder for other, unexpressed, arguments. It simply begs the question what the alignment should be. Any meaning it might be conceived to have is better expressed by the earlier arguments.

All the four serious arguments take their beginning in the observation that our, apparently universally spontaneously chosen, albeit somewhat nudged by the use of morals and clocks, traditional placement of our wake hours in the day is somewhat displaced towards the evening: we get up after rather than before sunrise, if the day is long enough, and tend to stay up after sunset, if the day is short enough. If the day is long enough, such as it is in summer at higher latitudes, but still short enough, such as it is at lower latitudes, a possibility presents itself, at middling latitudes, to experience more daylight during the waking hours by getting up earlier in summer.

There and Back Again

What are the reasons for ever turning the clock back again? In latitudes favourable to daylight saving time, in winter, the days are so short that nothing would be lost by staying in the early hourly pattern described by daylight saving time. So why don’t we? Well, since our preferred late pattern apparently was settled spontaneously, people would tend after some time to recreate it, postponing as it were all activities by one hour. In fact, we have an example of just this happening. In mainland Spain, an adjustment corresponding to daylight saving time was introduced during World War II and never reversed. Instead, Spaniards since then live their day an hour later. The effects of daylight saving time will tend to peter out with time. So a permanent regime of time displaced more than half an hour from solar time is a different proposition altogether from daylight saving time. It has different effects and needs different arguments. There is no such thing as permanent daylight saving time. For this discussion, therefore, I will stick to the kind of daylight saving time we know under this name. It seems, since its latest introduction in the 1980’s, to be permanent enough.

The Effects of Daylight Saving Time

The arguments for daylight saving time are, as we have seen, very simplistic. It is all a matter of whether the sun is up or not at certain points in time. I guess this is what makes it so very attractive to people who don’t like to think too much and too deep. Since, as previously noted, Earth revolves around its axis and around the sun at fairly constant velocities and at a fairly stable inclination, and the details thereof are well known, these arguments can easily be tested. I have created a simple calculation in an automated spread sheet and produced the following results:

Latitude Group 1 Group 2 Net
10°N no effect win 50 h win 50 h
20°N lose 23 h win 87 h win 64 h
30°N lose 25 h win 127 h win 102 h
40°N lose 23 h win 148 h win 125 h
50°N lose 14 h win 146 h win 132 h
60°N lose 12 h win 13 h win 1 h

Table 1. Effect of U.S. daylight saving time at different latitudes

The assumptions used in this calculation are the following: People get up at six o’clock, commute from seven o’clock to eight o’clock, work all day, commute back between five o’clock and six o’clock, eat dinner and then use the rest of the evening until sunset or at the latest nine o’clock for useful leisure activities. Later activities can be assumed to be of such kind, sleep or amusement, that the presence of sunlight is a disadvantage. I have, therefore, deducted extra, unwarranted sunlight in the late evening from the result for Group 2. This effect only occurs at latitudes above 47°N. Another way to express it is that the evenings at these latitudes are so long that it makes no sense in terms of good use of sunlight to place activities earlier in the day.

The values in the column marked Group 1 represent the net surplus of sunlit hours between 6:00 AM and 8:00 AM and between 5:00 PM and 7:00 PM, the time during which, according to the arguments in Group 1 above, less use of artificial lighting could lead to decreased power consumption and safer road traffic. Here daylight saving time fails miserably. More sunlit hours are lost in spring and fall than are recovered in summer. The main reason for this is that the switch to daylight saving time is made so early in the year and the switch back so late. This is visible if we compare with the effects of European-Union daylight saving time, which starts later and ends earlier:

Latitude Group 1 Group 2 Net
10°N no effect win 48 h win 48 h
20°N lose 16 h win 84 h win 68 h
30°N lose 18 h win 124 h win 106 h
40°N lose 21 h win 146 h win 125 h
50°N lose 14 h win 144 h win 130 h
60°N lose 10 h win 10 h no effect

Table 2. Effect of E.U. daylight saving time at different latitudes

But there is also a contradiction between the two groups of alleged advantages of daylight saving time. Nudging the parameters to make the one pay off more will necessarily remove the same amount of pay-off from the other. If we, e.g. assume that people get up later than six o’clock in the morning, the advantages of Group 1 arguments will increase. But then we must assume that they also stay awake longer in the evening, or even commute and sup later, nudging away at the other end of the day. It seems to me that the arguments in Group 1 were added later to the proposition of daylight saving time purely for the sake of persuasion. With a promise of energy conservation or road safety, almost anything can be sold. It was assumed no one would call the bluff, because if some one did, like I just did, the argument for daylight saving time would not be strengthened, but weakened, by these claims. Like they just were.

Turning now to the arguments for daylight saving time in Group 2, which were indeed the original ones, it is easy to see that they have some merit. Yes, the two hours following dinner will contain more daylight. Yes, getting started earlier in the morning, essentially eating breakfast and commuting in darkness, will allow more armaments to be produced in daylight before the sun sets.

We should be all set, then. Even if not all arguments made by proponents of daylight saving time actually hold water, the net effect is positive, at least in the middling latitudes where central Europe and the northern parts of the U.S. are located. There is just one thing. Frédéric Bastiat has taught us to consider not only that which is seen, but also that which is not seen. So let us have a look at that.

Saving Daylight for Workers in Factories

Roof lights

Let’s look a little closer at just what the advantages we just measured are. This picture shows the archetypal factory roof with tilted lights designed to maximize the amount of daylight hitting the factory floor. That is how factories looked during the First World War. Very suitable for daylight saving time indeed. But it is not how factories look now.

A modern car factory

As this picture of a Tesla car manufacturing plant shows, factories today use artificial lighting all day long. The Wikipedia page about light ergonomics doesn’t even mention sunlight. Manufacturing is not any longer a major part of our economy, as it was in 1916, and it is not as densely populated as it was then. Factories are to a large degree automated and run around the clock. Instead, people work in offices — on irregular hours. They may have flextime. They may be self-employed or set up home offices at Starbucks when it fits them. They may co-operate with colleagues in distant time zones. A hundred years later, there is no merit to this part of the argument irrespective of how many hours longer the sun is up during a normal working day.

Playing hockey in 1916

What about sun-lit leisure time? In 1916, leisure activities were simple and preferably outdoors. Today, people spend their free time indoors in windowless shopping malls, in computerized social networks or in front of television sets. People ride escalators to reach indoor gyms where they perform scientifically designed repetitive movements in artificial light. The attractiveness of trading off darker mornings for lighter evenings for the sake of having fun is quickly diminishing.

Rowing for pleasure

To sum it up, daylight saving time has no merit any more for increasing productivity through the increased use of daylight nor for increasing either the quantity or the quality of workers’ leisure time in the evening. Attempting to give workers in factories, or even in offices, more daylight at and after work is solving the wrong problem. Judged by the arguments openly proposed, daylight saving time is way past its use-by date. We have moved on and should have left it behind. How come we didn’t? There must be something else at work below the factory floor.

Dig a Little Deeper

Perhaps you have clicked on the link called 50°N in the tables above, since that is where the largest effect of daylight saving time can be seen. If not, try it out now, or even better follow this link: 51°N. Take a look at where these latitudes pass through Germany: North Rhine-Westphalia, Rhineland-Palatinate. Right in the middle of the central German industrial area, or rust-belt if you will. Here, the most hours of afternoon  and early evening daylight can be won in summer by a scheme of daylight saving time. This should make it pretty clear why it was the Germans who first used daylight saving time in 1916 in order to augment output of ordnance during the Great War. Everyone else followed suit for the obvious psychological-sociological war-time reasons of boosting morale by appearing to act decisively and of visibly tightening discipline by increasing regulation. As we saw above, daylight saving time might even, at that time, have worked as designed. But the moral, sociological, effect obviously is much more persuasive and powerful to humans than the underlying technocratic calculation. During the Second World War, the United Kingdom even used double daylight saving time. Given that Great Britain is located so far north as to make daylight saving time less efficient, this was not a matter of using daylight efficiently any more. The moral aspect, the meme effect, was taking over. Double daylight saving time was intended as, and worked as, a crack of the whip on the back of the British, and most likely a needed and useful one in a desperate situation. Viewed in this light, there seems to be more than mere coincidence behind the fact that our current incarnation of daylight saving time was instigated at the crossing point of the Oil Crisis and the height of the Cold War.

A Mobilization Effort

By looking beyond the ostensible arguments, we can now evaluate the utility of daylight saving time for what it apparently in reality is — a mobilization effort. For what war, you might ask. The Oil Crisis and the Cold War both ended, but daylight saving time did not. At least not in the West. What happened?

After the Cold War and the Oil Crisis, we got Globalization and free international trade and competition. There is a wonderful German word connected to this called Wirtschaftsstandort: how attractive (politicians think) a place is for running a business in. Apparently, after the end of the Cold War and the Oil Crisis, the rulers of the West stuck to daylight saving time either for reasons of gross political ineptitude or for increasing gross national output in order to compete better, at a bloc level, on international markets — improving the Wirtschaftsstandort, as it were.

Let us therefore now assume that daylight saving time is not really about saving energy or preventing road accidents, because it can’t and it doesn’t. Let us also assume that daylight saving time is not really about allowing us to use more sunlight for professional or recreational purposes, even though it could, because we don’t. Let us instead assume that daylight saving time is about raising the gross domestic product — not by illuminating factories, but by mobilizing and motivating the workforce. If it has such an effect, it should be visible as a difference between the growth rates of countries with daylight saving time and countries without it. This graph shows world-wide GDP growth during the period 1990 to 2006: (source: Wikimedia Commons)

GDP accumulated change

Among the leaders in sustained GDP growth, China, Hong Kong, India, South Korea, Singapore and Taiwan all refrained from using daylight saving time during most or all of the time period from 1990 to 2006. Even if daylight saving time has an effect of mobilizing and motivating the workforce, the effect is minor and difficult to detect. As can be seen in this graph, had we wanted to raise our gross domestic product, we should have used measures other than daylight saving time. It can be done.

So that is it. Judged either by the technocratic arguments commonly presented or the sociological ones which apparently lurk behind them, daylight saving time is plain useless. It does none of the things it is supposed to do, openly or secretly. It is a change for change’s sake, a social motion without meaning. At the very least, you say, clutching at straws now, daylight saving time could be something keeping us together and defining who we are. We are not the knights who say “ni!”. We are the countries who toss with our clocks. What is the harm in a little useless social ritual?

Let us have a look at that.

Time Travel versus Inertia

The most obvious and egregious flaw in the scheme of daylight saving time is the assumption that changing the clock time in spring and autumn has no other implication than that the activities of the day occur at other angles to the sun. It is for a person with even rudimentary training in physics incomprehensible how one could make this assumption, since the desired condition could be the result only of instantly turning Earth around its axis 18 degrees forward or backward without interfering at all with its otherwise fix rotation — something obviously requiring, among other things, infinite amounts of energy and infinitely fast movement. Just setting our clocks forward or backward by one hour is not an actual equivalent to this operation. The arguments for daylight saving time just assume it is, but in the real world, inertia beats time travel every time.

It Is Just a Jet Lag

Since, in order to enact daylight saving time, we move the little hands of our clocks, and not Earth itself, the inertia that beats time travel is located not under our feet, but in our inner clock, which doesn’t possess a little hand that can be easily manipulated. Sometimes, attempts are made to play down the adverse effects of switching to and from daylight saving time by comparing its effect with those of a small jet lag. This false analogy is actually very illustrative.

Anyone who has experienced one knows that the way to handle a jet lag is to use one’s body’s ability to spontaneously adapt itself to the local time as sensed by the timing of familiar customs such as meals but primarily by the diurnal pattern of sunlight. Staying awake is an act of will, falling asleep is a blessing; but actually adapting to the local time is a bodily exercise. A jet lag occurs because clock time and sun time both changed. We cancel a jet lag by gradually adopting the local sun time, which influences our inner clock and over time moves it towards the local clock time. This is the exact opposite of daylight saving time, which is moving clock time, and allegedly body time, independently of sun time. When we change the time on our clocks for daylight saving time, sun time stays the same. Our inner clock gets no cue as to what this change is supposed to be. This is the reason that setting the clocks forward or backward is much worse than an ordinary jet lag. This is why effects such as tiredness, sleeplessness, headaches, lowered productivity and an increase in heart attacks and in traffic accidents accompany the switches into and out of daylight saving time in spring and autumn.

Sleep Is for the Weak

If the time changes in spring and autumn has such severe adverse effects, what about the time in between? The calculations I described above were based on the assumption that people adapt completely to daylight saving time and live their lives in exactly the same way, only an hour earlier, in summer. Only, that doesn’t seem to be what actually happens. What people say they like about daylight saving time is the light summer evenings suitable for playing golf and having a barbecue. This is why the sports and barbecue equipment manufacturers form the strongest lobby for keeping daylight saving time.

Now since these light summer evenings are caused by Earth’s fixed rotation around its own axis and around the sun, and so — with the same weather and the same temperatures — were there all the time, with or without daylight saving time, what has changed? What has changed is that people in effect get up an hour earlier in the morning by keeping their alarm bells set at the same clock time as in winter. To put it another way: Because of daylight saving time, people tend to sleep less in summer. That is what happens when you get up earlier in the morning. There is no alarm clock calling us to go to bed one hour earlier during daylight saving time, and the relatively lighter summer evenings nudge us to stay up. We can use our will to wake up or stay awake, but most of us cannot use it to fall asleep or to keep sleeping. This tendency to deprive us of sleep is yet another way in which daylight saving time causes health problems and low productivity.


Daylight saving time is a policy with no advantages whatsoever, except perhaps in times of utter desperation, but with plenty of severe disadvantages. It is comparable to cutting ones own flesh for no obvious reason; it is self-harm at the political level, it is flagellation on the back of the body politic.


The attitudes in a polity towards daylight saving time is nothing more and nothing less than a pure measure of the political ineptitude and irrationality of that polity. Daylight saving time is, in times of peace and in times of war, a symptom of political illness. And that is what qualified it to become a theme on this blog, which is dedicated to explaining and vilifying political ineptitude and irrationality.

If you are the victim of daylight saving time, then you belong to a polity ruled in irrationality. You should get active and do something about it.

One thought on “Daylight Saving Time

  1. Living within the limits of the tropics, changing the clock is not of much use. The sun sets a little later but all in all it rises at six and night falls at six. The children suffer getting up in the dark, air condition in the homes must be used more when coming home earlier. I hope the strange reasons here for changing the clocks, ”energy saving”, ”coordinating hours with Europe (being in Latin America)”, etc etc, would be questioned soon, so we can get rid of this stupid idea. Hopefully we will, when they get rid of the ”summer time” in Europe. Thank you for an interesting article. I would certainly hope the politicians here could read English…. and your article.


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