Daylight-screwing-up time

comes around again for North America, in the night between today and tomorrow.

You’re supposed to screw your clock forward by an hour at 2 AM on the second Sunday in March. At 2 AM, mind! Be good and do what Congress tells you. You’ll be able to pass the time between Saturday and Sunday by watching Jupiter move over the meridian and Mars, Saturn, and Antares come into view.

horizon scene 2015 March 13 2 AM

The moment you screw your clock forward an hour, 2 AM becomes 3 AM. From then on, you are living by this untrue time (untrue to the motion of the Sun) for the next eight months. (Britain has another two weeks of natural time before its seven unnatural months begin.)

We would all like to exercise power over time, but only governments are vain enough to imagine they can do it. On August 7, 2015, North Korea announced that it would turn time half an hour back, moving into a time zone of its own (Greenwich Mean Time plus 8:30 instead of plus 9) that would separate it from South Korea and Japan.


The announcement by state television station KCNA said that the change would come into effect on August 15, 70th anniversary of Korea’s liberation from Japan at the end of World War Two. “The wicked Japanese imperialists committed such unpardonable crimes as depriving Korea of even its standard time while mercilessly trampling down its land with 5,000-year-long history and culture and pursuing the unheard-of policy of obliterating the Korean nation.”


25 thoughts on “Daylight-screwing-up time”

  1. Guess I’ll have to admit to being in the minority (at least among the folks here) and say I have no issues with DST. I’m in Ohio on the western edge of the Eastern time zone, and without DST the sun would be rising for us at 5 a.m. in June rather than 6 a.m. I’d rather have the daylight at the end of the day, since I’m always up at 9 p.m. but not often at 5 a.m. What clinches it for me is that at the opposite end of the Eastern zone it’s even worse–if we stayed on standard time folks in northeastern Maine would be having sunrise before 4 a.m. with sunset at 7:30 p.m., which just seems totally pointless to me.

    1. Yes, our hankering for the simplicity of unshifted clocks is probably a lost cause, a nostalgia, because it’s founded on the different older way of organizing human time: starting wprk at a time related to the sunrise, rather than to a number. It was an enormous political operation to make everybody use the clock-change, but it was done; which suggests that though it would also be an enormous operation to move citizens onto a system in which schools start, shops stay open, etc., at times adapted to season and latitude, it might not be impossible.

      1. At latitude 40 degrees, the sun is up 13.5 hours on average in spring and summer, and 10.5 hours in fall and winter. So, to expand on your thought of adapting school and work hours to the length of daylight, I would suggest:

        Vernal equinox to Autumnal equinox: School and work hours should be 7 to 5.
        Work: 10 hours
        Personal time: 8 hours (3.5 hours in daylight)
        Sleep: 6 hours

        Autumnal equinox to vernal equinox: School and work hours should be 8 to 4.
        Work: 8 hours
        Personal time: 8 hours (2.5 in daylight)
        Sleep: 8 hours

        I believe this is correct biologically (emphasis on logically).

        1. You’ve gone further into thinking about this than I have, so I store your ideas for future reference if we take up a campaign for life-adapting (instead of clock-shifting) time. As yet it ranks in urgency behind the campaigns for keeping Britain in the European Union, saving the planet from global heating, and some others.

          I notice that you estimate 6 hours as appropriate for sleep in summer, 8 in winter. I wasn’t aware of this difference. I think of 6 hours as about my maximum for sleep, but there are personal uncertainties because some (like me) are very irregular sleepers and because sleeping time could refer to time in bed or time actually sleeping, which can be very different!

          And work-hours: 10 in summer, 8 in winter. This is also very interesting, and likely to provoke interesting debate!

          1. I’ve heard that in Scandinavia they work longer hours in the winter and shorter hours in the summer, so they can spend more time outdoors in the summer. But I don’t know if this is true.

          2. I think humans tend to sleep longer in cold weather, sort of like bears but not as extreme.

            As far as the 10 hour workday, I look at it as an extra 25% in income.

          3. There’s nothing wrong with working fewer hours if you can afford it. I enjoy doing chiropractic adjustments and teaching yoga, but I like being on vacation even more. My goal is to save enough to be able to survive on investment interest, and work less hours in both summer and winter.

  2. So much for North Korea being able to tell time – DST or otherwise. Without checking any history books, I would guess that N Korea was freed from Japan 71! years ago – in 1945.

    1. Dave, they may be as bad at subtraction as I am, but I think I did say that when they did this was August last 2015.

  3. I am pleased that there is a bill in the California State Assembly to put a measure before the voters to repeal daylight saving time in California. Assembly Bill 2496, by Assemblyman Kansen Chu of San Jose. Because daylight saving time was established by voter initiative in California in 1949, only another vote of the people could repeal it. But I think repeal would have a good chance of passing. I’ve written the following message to my own Assemblyman, David Chiu, and a slightly modified version to my State Senator, Mark Leno:

    Dear Assemblyman Chiu — Please support Assembly Bill 2496, by Assemblyman Kansen Chu of San Jose, to put an initiative on the ballot to repeal daylight saving time in California. Daylight saving time does not save energy or promote public safety. Rather this irrational annoyance is associated with an increase in accidents, heart attacks, and strokes. Arizona does just fine without daylight saving time. California would too.
    Thank you for your consideration, and for your service to the people of San Francisco.

      1. No joke. Forcing the body clock to move forward an hour is stressful, and if somebody is already at risk of heart attack or stroke, that stress can be enough to push you over the edge.

  4. We moved from Connecticut (eastern-most of the Eastern Time Zone) to Indiana (western-most of the Eastern Time Zone) midsummer of 2005. I looked forward to not dallying with clocks twice a year.
    Unfortunately, within our second year of residency, the Powers-That-Be decided to turn Indiana from “A Natural State” to another unnatural one, screwing with us once again as well as a whole state full of people who had not been previously bothered with such unnecessary drivel.

    1. Good story! Maybe you should move to Arizona or Hawaii. Or maybe not, lest you bring them the same bad luck!

  5. As I understand matters, local noon is defined by the time the sun crosses the meridian. I live in Ann Arbor in the Eastern Time Zone, about 600 miles west of New York City, also in the Eastern Time Zone. NYC local noon was 12:05 EDT (3/11/16). Local noon in Ann Arbor on the same day was 12:45 EDT. On Michigan’s Lake Michigan coast, also in the EDT is even worse with local noon being around 12:54 EDT. So our time is screwed up regardless of the date. The result is having astronomical twilight end around 23:30 near the summer solstice.

    The obvious proposal would be to make Ann Arbor the Prime Meridian, and hang Daylight Savings Time, but somehow I doubt that will happen.

    1. Yes, the time the sun crosses the meridian gives local apparent (i.e. observed) time. Averaging it for a fictitious constantly moving sun gives mean solar time, the first departure. Making it a standard time all over a zone is the next departure, and would mean that some places are a half hour off even if the zones were geographically equal. The whole-hour shift of “Daylight-Saving” time is the greatest departure, except for some time zones that are drawn so that places in them can have times even further away from local solar – e.g. China, all one time zone, and Europe, one zone from Spain to Sweden.

      1. I deal with DST by remembering your poetic statement, “From May to October , subtract only 4 hours.”

        DST is an unnecessary inconvenience, but I’m already used to sidereal time being slower than clock time. Living in Cleveland, in the western portion of the Eastern Time Zone, the stars and planets are almost an hour late even in Standard Time.

        I love this post because I thought I was alone in my deprecation of DST. Most others in my circle of friends like it because they like the later sunset.

        I think you once wrote, “DST is like cutting the tail off a dog and glueing it to his head and saying you’ve made the dog longer.”

        1. I think that saying about the dog’s tail came from a Native American, I can’t at the moment track it down.

  6. For years, I have worn a 24 hour wrist watch equipped with a 24 hour rotating bezel. The watch is set to Greenwich Mean Time, and the outer bezel is set to local standard time or daylight time, as required. When I am at my telescope, I always use standard time, and reluctantly return to using DST afterwards. I would do away with DST without question or pause.

      1. That would be fun. But, I do have a sidereal clock with me in the field. I bought a cheap drug store windup clock that was equipped with a fast-slow adjustment. I adjusted it to provide the sidereal rate, and check its accuracy with the Celestial Dome!

    1. Does your watch face have the 24 / 0 hour at the bottom or the top? I much prefer having the 24 / 0 hour at the bottom and the 12 hour at the top, so that the hour hand culminates at (approximately) the same time as the Sun.

      1. No, and I cannot say “unfortunately”, either. Truth is that in practise it doesn’t really matter. Although there are those 24 hour watchfaces that have noon at culmination (that is kind’a cool), this one does not. It’s an old Falcon Airman GMT 3000, designed as a navigator’s chronometer: black face, white markings, sweep second hand. No other capability but accurate time. I wear it every day.

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