Turning clocks away from natural time for more than half the year was a lousy idea. Some people now want this distortion to be imposed for the whole year. They appear not to know the purpose for which the clock-falsifying was introduced in the first place. Its supposed usefulness was adaptation to the changing time of sunrise. Imposing it for the whole year removes any such usefulness, leaving only the unnaturalness.
The untrue time is called Daylight Saving Time in North America, Summer Time in Britain. The late beloved astronomy writer George Lovi called it Daylight Displacement Time, since no daylight is “saved.” That’s good. My alternative is Daylight Shifting Time. It consists of turning clocks forward an hour in spring, and returning them to natural time in autumn, by law.
The undistorted time, which for simplicity I call natural time, is the Standard Time for your time zone. It is solar time, a measure of the position of the Sun. More exactly, it is the “local mean time” for the standard longitude of your time zone, meaning that it ignores the slight differences in the length of the day caused by Earth’s slightly varying speed in its orbit.
The basic objection to the fooling with clocks is that it makes a lie of our whole historical concept of day-and-night time. Zero is supposed to be the midpoint of the night, when the Sun is deepest below the horizon. The hour twelve is supposed to be half way around the cycle, when the Sun is highest, crossing the middle of the sky.
This picture of the Sun’s path is for latitude 40° north (as in the U.S. or the Mediterranean). It is calculated for a date near to the spring equinox and the spring clock-change, but I’ve chosen April 15 because that is a date when the “equation of time” is zero, meaning that there is no complication from the Sun’s slightly varying speed. For any other date the picture would be essentially the same but with the arch of the path higher or lower.
The vertical white line is the meridian – a word whose origin is Latin medidies, “middle day.”
The white symbols are at the Sun’s positions, by natural time, at 6 AM, midday, and 6 PM. The red symbols are at the times one hour earlier – 5 AM, 11 AM, and 5 PM, which the clock-change rule forces us to call “6 AM,” “midday,” and “6 PM.”
The Sun travels about 15° in an hour, and is (surprisingly) only half a degree wide. In the picture it is exaggerated 4 times in size – otherwise it would be a dot. So the difference between false and true positions is even more than the picture might convey.
In a comment on my March 8 post, Rick Scheithauer gave us a handy list of some of the practical objections to “Daylight Saving Time”:
1) DST complicates expression of time for astronomical events (Guy’s main DST objection).
2) High noon can no longer be an accurate description of 12 o’clock, complicating children’s concept of reality.
3) Changing opening and closing times of businesses and outdoor tourist attractions is hard enough when basing times on latitude without the added confusion of DST.
4) Falling asleep is more difficult when daylight is abnormally long in the evening.
5) Many people in our population (the early risers, probably a majority) would rather have more daylight at the beginning of the day, when their energy is highest, rather than at the end of the day, when their energy is subsiding.
There is more to be said about latitude (how far you are from Earth’s equator). It strongly affects sunrise and sunset times. Compare these three graphs: for 60 degrees north (as in northern Scotland, southern Norway, or a band of Canada), 40 north (the mid-northern U.S.), and 25 north (Florida).
The gray zones are three depths of twilight (civil, nautical, and astronomical, defined as when the Sun is less than 6, 12, and 18 degrees below the horizon). The black area is deep dark night.
The three green vertical lines represent 6 in the morning, midday, and 6 in the afternoon.
The red lines show what clocks in North America are told to do with those times. And orange lines show the slightly different rule in Britain.
One rule does not fit all latitudes.
The only rule that would is adapting to the daylight: changing not clocks but opening hours to suit the swing of sunrise in your part of the world. Roll with the Sun.
I could have added another set of lines on these graphs: straight lines all the way down at the “shifted 6 AM,” “shifted middayM,” and “shifted 6 PM” positions.
These would represent the year-round clock times proposed in the “Sunshine Protection Act” (ironic name) introduced by Senator Marco Rubio, of Florida. Florida, being at the southern edge of the U.S., experiences little change in sunrise time through the year, which could be why Senator Rubio agrees with returning to a steady time throughout the year. He needs to understand that the good time to return to is Standard Time.
Rick Scheithauer in a second blog comment shows us the letter he has sent to Rubio and others, supporting one-time-all-year but giving more fully argued reasons why it should not be “Daylight Saving Time.” Please take another look and consider Rick’s suggestion that you send the same or a similar letter to your own lawmakers.
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DIAGRAMS in these posts are made with precision but have to be inserted in another format. You may be able to enlarge them on your monitor. One way: right-click, and choose “View image”, then enlarge. Or choose “Copy image”, then put it on your desktop, then open it. On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers). I am grateful to know of what methods work for you.
I suspect that the prevalence of bright artificial light all night long contributes to the popularity of year-round daylight saving time. Many people never experience darkness, so they never notice dawn, and dusk is just an inconvenience. They’ve been brainwashed into expecting that the Sun should shine 24 hours every day. This is just one instance of how dangerously disconnected from reality we are becoming.
I’ve become resigned to daylight saving time. I put my digital clocks on DST and keep my analog clocks on standard time. Every morning I keep track of the times of sunrise, local solar noon, sunset, and local midnight *. I correct my friends and coworkers when they refer to 12:00 daylight time as noon. The biggest practical effect is that I have to start work at 7:00 am standard time for eight months of the year. In a few years I’ll retire, and it won’t matter any more. They can do what they want with the clocks. The Sun will still rise in the morning and set in the evening.
* As well as the times of moonrise and moonset, the Moon’s phase, ecliptic latitude, and relative distance from the Earth; when the planets rise and set; and which stars are visible in the nighttime sky.
A footnote to the footnote: the Moon’s declination as well.
The key part is “One rule does not fit all latitudes. The only rule that would is adapting to the daylight: changing not clocks but opening hours to suit the swing of sunrise in your part of the world. Roll with the Sun.”
Leave standard time alone, but just change the start and end times of businesses and schools as needed during the year.
The problem with this statement is that businesses and schools will probably not change start times as needed. Schools in particular are so rigid with rules that I cannot imagine them making any changes.
I live at 40 north in New Jersey, USA. Once the weather starts getting warm and the clocks change early evening activity increases including baseball and other sporting events until the heat sets in around late June which is made possible by having sunsets much later than school dismissal time, 7 PM – 8:30 PM.
The average worker gets home at around 5:30 PM. Parents have time to go see their children participate in these events. If the clocks were not changed the sunsets would be 6 – 7:30 PM. Workers would have to ask their employer to let them come in early and leave early to attend these events, and my guess is that not many employers would comply. Daylight saving time is a way to ensure all institutions comply.
Another point is that in June the sun would come up at around 5 AM or earlier from May to July if standard time ran all year. I doubt many people are out and about at 5 AM. All of that daylight is wasted for most of the population.
The point is that not many institutions would “roll with the sun”, depriving people of the opportunity to enjoy daylight after work and school while hours of daylight are wasted in the wee hours of the morning.
We get more daylight in the summer naturally, without adjusting the clocks. It comes both in the morning and the evening. So the semiannual headache of changing clocks really gains only 30 minutes more light in the evening than we get naturally – at its maximum.