DST (2018)

[KEVIN_224]

The sunset for Hartford, CT on Sunday was 6:00 PM even. I'll remember that come November 4th!

Much of Europe sets their clocks back this Sunday the 28th.

[webny99]

Yeah, mid-October would be a really good time for DST to end. October mornings are very challenging. Also, Halloween should occur after DST ends.

[tradephoric]

Yeah, mid-October would be a really good time for DST to end. October mornings are very challenging. Also, Halloween should occur after DST ends.

Mid-October mornings would be especially challenging if there was a time change to deal with.  A recent study found that there was a 11% increase in in the incidence rate of unipolar depressive episodes during the transition from summer time to standard time.  OTOH, no increases in unipolar depressive episodes were seen when transitioning from standard time to summer time. 

Daylight Savings Time Transitions and the Incidence Rate of Unipolar Depressive Episodes
https://journals.lww.com/epidem/Fulltext/2017/05000/Daylight_Savings_Time_Transitions_and_the.7.aspx

Background: Daylight savings time transitions affect approximately 1.6 billion people worldwide. Prior studies have documented associations between daylight savings time transitions and adverse health outcomes, but it remains unknown whether they also cause an increase in the incidence rate of depressive episodes. This seems likely because daylight savings time transitions affect circadian rhythms, which are implicated in the etiology of depressive disorder. Therefore, we investigated the effects of daylight savings time transitions on the incidence rate of unipolar depressive episodes.

Methods: Using time series intervention analysis of nationwide data from the Danish Psychiatric Central Research Register from 1995 to 2012, we compared the observed trend in the incidence rate of hospital contacts for unipolar depressive episodes after the transitions to and from summer time to the predicted trend in the incidence rate.

Results: The analyses were based on 185,419 hospital contacts for unipolar depression and showed that the transition from summer time to standard time were associated with an 11% increase (95% CI = 7%, 15%) in the incidence rate of unipolar depressive episodes that dissipated over approximately 10 weeks. The transition from standard time to summer time was not associated with a parallel change in the incidence rate of unipolar depressive episodes.

Conclusion: This study shows that the transition from summer time to standard time was associated with an increase in the incidence rate of unipolar depressive episodes. Distress associated with the sudden advancement of sunset, marking the coming of a long period of short days, may explain this finding. See video abstract at, http://links.lww.com/EDE/B179.

Below is the most interesting paragraphs of the study to me.  Any potential benefits of having more sunlight in the morning when transitioning from summer time to standard time was offset by the phychological effect of the sudden loss of sunlight in the evening.

The fall daylight savings time transition thus entails increased exposure to sunlight in the morning and decreased exposure to sunlight in the evening. As depression can be treated effectively by bright light therapy in the morning, especially in individuals with a phase-delayed circadian misalignment, who are overrepresented among those with unipolar depression, we would expect increased exposure to sunlight in the morning to decrease the incidence of unipolar depressive episodes. Instead, we observed the opposite and can therefore rule out this explanation.

This observation means that other mechanisms than those outlined above must be at play to explain the increased incidence in unipolar depressive episodes at the transition from summer time to standard time. One possible explanation is that the sudden advancement of sunset from 6 pm to 5 pm (Figure 4), which in Denmark marks the coming of a long period of very short days, has a negative psychological impact on individuals prone to depression, and pushes them over the threshold to develop manifest depression. Furthermore, individuals having previously developed depression in the winter (as part of seasonal affective disorder) may perceive the transition from summer time to standard time as an omen of a new depression to come, which could have a depressogenic effect in itself. Some may argue that we should then observe an opposite effect, that is, a reduction in the incidence rate of unipolar depressive episodes, at the transition from standard time to summer time in the spring. However, the absence of such an effect could be explained by a valence-specific cognitive bias (i.e., an inclination to focus on negative events or emotions rather than positive ones), which is a well-known feature of unipolar depression.

[jp the roadgeek]

The strange thing I've noticed is that we set our clocks ahead much closer to the vernal equinox than we set our clocks back after the autumnal equinox. If we were to balance it out, we would either have to set our clocks back either the last Sunday in September or the first Sunday in October.  Or, we would have to set our clocks ahead the first or second Sunday in February.  Of course, the first Sunday would  never fly because you'd be combining it with Super Bowl Sunday.  But I wouldn't mind going DST in mid February, as February is such a dull, depressing month once the Super Bowl is over; that extra hour of daylight would be a spirit booster.

[english si]

But I wouldn't mind going DST in mid February, as February is such a dull, depressing month once the Super Bowl is over; that extra hour of daylight would be a spirit booster.

Yes, because DST magically slows the earth's rotation to give you more daylight. 

[kphoger]

I still don't understand how "noon should be close to midday" is contestable.  Sunrise here is currently 4.8 hours before 12:00, while sunset is 6.7 hours after 12:00.  That just bothers me in general.  The sun should be at its highest point close to 12:00.

Heck, if nobody cares about morning sunlight and wants extra daylight in the evening, then....  Let's assume people wake up at 6:30 AM and go to bed at 10:30 PM, and let's work with 14 hours of daylight in one of the warmer months.  Then let's just change the clocks so the sun rises at 8 AM and sets at 10 PM.  Everyone should be SUPER happy then.

[hotdogPi]

I still don't understand how "noon should be close to midday" is contestable.  Sunrise here is currently 4.8 hours before solar noon, while sunset is 6.7 hours after solar noon.  That just bothers me in general.  The sun should be at its highest point close to 12:00.

The obvious argument: Most people are awake at 8 PM. Most people are not awake at 4 AM.

However, this does not necessarily mean that the sun should follow the same times as when people are awake (see vdeane's responses about circadian rhythm).

[kalvado]

I still don't understand how "noon should be close to midday" is contestable.  Sunrise here is currently 4.8 hours before solar noon, while sunset is 6.7 hours after solar noon.  That just bothers me in general.  The sun should be at its highest point close to 12:00.

Why should it be that way?  I see zero reasons, and I advocate solar noon (as in highest position of the sun),  at 1-2 PM as a most convenient timing. That is permanent DST, after all.
BTW, make sure you use "solar noon" properly, it is not the same as 12.00 noon on the clock.

[kphoger]

I still don't understand how "noon should be close to midday" is contestable.  Sunrise here is currently 4.8 hours before solar noon, while sunset is 6.7 hours after solar noon.  That just bothers me in general.  The sun should be at its highest point close to 12:00.

The obvious argument: Most people are awake at 8 PM. Most people are not awake at 4 AM.

However, this does not necessarily mean that the sun should follow the same times as when people are awake (see vdeane's responses about circadian rhythm).

I agree that the sun should not follow the same times as when people are awake, because doing so would assume we all sleep an average of 12 hours per day.

I still don't understand how "noon should be close to midday" is contestable.  Sunrise here is currently 4.8 hours before 12:00, while sunset is 6.7 hours after 12:00.  That just bothers me in general.  The sun should be at its highest point close to 12:00.

Why should it be that way?  I see zero reasons, and I advocate solar noon (as in highest position of the sun),  at 1-2 PM as a most convenient timing. That is permanent DST, after all.
BTW, make sure you use "solar noon" properly, it is not the same as 12.00 noon on the clock.

Because that's the way it was developed.  It's the whole reason we even have phrases like "high noon" and "solar noon".  Hell, it's even where we get the terms "AM" and "PM".  (And yes, I mis-typed.  I've corrected the "solar noon" thing in my post.)

[tradephoric]

I still don't understand how "noon should be close to midday" is contestable.  Sunrise here is currently 4.8 hours before solar noon, while sunset is 6.7 hours after solar noon.  That just bothers me in general.  The sun should be at its highest point close to 12:00.

The obvious argument: Most people are awake at 8 PM. Most people are not awake at 4 AM.

Assuming a typical schedule of waking up at 6AM and going to bed at 11PM, that person would have finished half of their waking day at about 2:30PM.  Shifting the typical schedule an hour earlier (5AM wake up/10PM go to bed), then half the day would be at 1:30PM.  Cultural "half day point" lining up with the sun being at its highest point doesn't seem totally unreasonable. 

However, this does not necessarily mean that the sun should follow the same times as when people are awake (see vdeane's responses about circadian rhythm).

A recent study analyzing 185,419 hospital contacts for unipolar depression found that there was a 11% increase in the incidence rate of unipolar depressive episodes during the transition from summer time to standard time.  Even as sunlight is shifted to the morning after the fall time change, there was a spike in depression (presumably because the sunset was suddenly an hour earlier... just as people are ready to relax after coming home from school/work it's already pitch dark out).  This study goes against conventional wisdom (IE. vdeane's responses).   

The fall daylight savings time transition thus entails increased exposure to sunlight in the morning and decreased exposure to sunlight in the evening. As depression can be treated effectively by bright light therapy in the morning, especially in individuals with a phase-delayed circadian misalignment, who are overrepresented among those with unipolar depression, we would expect increased exposure to sunlight in the morning to decrease the incidence of unipolar depressive episodes. Instead, we observed the opposite 

https://journals.lww.com/epidem/Fulltext/2017/05000/Daylight_Savings_Time_Transitions_and_the.7.aspx

[kalvado]

I still don't understand how "noon should be close to midday" is contestable.  Sunrise here is currently 4.8 hours before 12:00, while sunset is 6.7 hours after 12:00.  That just bothers me in general.  The sun should be at its highest point close to 12:00.

Why should it be that way?  I see zero reasons, and I advocate solar noon (as in highest position of the sun),  at 1-2 PM as a most convenient timing. That is permanent DST, after all.
BTW, make sure you use "solar noon" properly, it is not the same as 12.00 noon on the clock.

Because that's the way it was developed.  It's the whole reason we even have phrases like "high noon" and "solar noon".  Hell, it's even where we get the terms "AM" and "PM".  (And yes, I mis-typed.  I've corrected the "solar noon" thing in my post.)

So what? Things were developed in funny ways, but it doesn't affect how we use them today. Thursday is now longer the day of the god Thor, for one - and October is no longer the eighth month of a year....

[kphoger]

So what? Things were developed in funny ways, but it doesn't affect how we use them today.

It makes about as much sense as shifting our temperature scale by 10° because people get hot at around 90° instead of 100°.

[kalvado]

So what? Things were developed in funny ways, but it doesn't affect how we use them today.

It makes about as much sense as shifting our temperature scale by 10° because people get hot at around 90° instead of 100°.

I agree that starting working day at 7, having wakeup time at 5 and bedtime of 9-10 PM is a better option. But if we cannot make people go to bed at 9, we have to make sure clocks read 11 PM at 9...
And yes, the shift should be by 32 deg, with a unit scaled by a factor of 0.555

[kphoger]

So what? Things were developed in funny ways, but it doesn't affect how we use them today.

It makes about as much sense as shifting our temperature scale by 10° because people get hot at around 90° instead of 100°.

I agree that starting working day at 7, having wakeup time at 5 and bedtime of 9-10 PM is a better option. But if we cannot make people go to bed at 9, we have to make sure clocks read 11 PM at 9...

And now we're back to Benjamin Franklin's parody again...

(1) Let a tax be laid of a louis per window, on every window that is provided with shutters to keep out the light of the sun.

(2) Let ... guards be placed in the shops of the wax and tallow chandlers, and no family be permitted to be supplied with more than one pound of candles per week.

(3) Let guards also be posted to stop all the coaches, &c. that would pass the streets after sunset, except those of physicians, surgeons, and midwives.

(4) Every morning, as soon as the sun rises, let all the bells in every church be set ringing; and if that is not sufficient?, let cannon be fired in every street, to wake the sluggards effectually, and make them open their eyes to see their true interest.

All the difficulty will be in the first two or three days; after which the reformation will be as natural and easy as the present irregularity; for, ce n'est que le premier pas qui coûte. Oblige a man to rise at four in the morning, and it is more than probable he will go willingly to bed at eight in the evening; and, having had eight hours sleep, he will rise more willingly at four in the morning following.

And yes, the shift should be by 32 deg, with a unit scaled by a factor of 0.555

I see what you did there, and I knew you'd do it, and it's not at all what I said.

[vdeane]

A recent study analyzing 185,419 hospital contacts for unipolar depression found that there was a 11% increase in the incidence rate of unipolar depressive episodes during the transition from summer time to standard time.  Even as sunlight is shifted to the morning after the fall time change, there was a spike in depression (presumably because the sunset was suddenly an hour earlier... just as people are ready to relax after coming home from school/work it's already pitch dark out).  This study goes against conventional wisdom (IE. vdeane's responses).   

I'd be curious about comparing the last week of February/second week of October (which have similar daylight lengths, just offset about 40 minutes from each other due DST and the tilt of the Earth) as a way to compare typical conditions in each period in about as close to an apples to apples comparison as one can get.  That way the findings wouldn't be affected by the sudden jolt around DST.

[kalvado]

I see what you did there, and I knew you'd do it, and it's not at all what I said.

What we are talking about is adjustment of general population daily schedule with respect to solar cycle. Clock is an instrument of synchronizing these individual schedules with each other and astronomy (sun position),  nothing more. 
Moreover, use of this tool did  change over time, from each city having its own time to time zones with uniform time to DST - all of these degrading your "solar noon at 12.01 PM" approach, but allowing better schedule synch and presumably convenient alignment of solar cycle to... lets call it business cycle of human life.
So I don't see anything wrong with further degradation of "solar noon sets clock" concept - as long as modern requirements to clock settings (synch of schedule for many people across the globe and convenient - not numerically precise - alignment of solar cycle) are achieved.
I am pretty sure that 12=noon concept was largely independent on everyday life of most population back when it was used, as people worked sunrise to sunset in the field and whistle to whistle in most factories....

[kphoger]

I see what you did there, and I knew you'd do it, and it's not at all what I said.

What we are talking about is adjustment of general population daily schedule with respect to solar cycle. Clock is an instrument of synchronizing these individual schedules with each other and astronomy (sun position),  nothing more. 
Moreover, use of this tool did  change over time, from each city having its own time to time zones with uniform time to DST - all of these degrading your "solar noon at 12.01 PM" approach, but allowing better schedule synch and presumably convenient alignment of solar cycle to... lets call it business cycle of human life.
So I don't see anything wrong with further degradation of "solar noon sets clock" concept - as long as modern requirements to clock settings (synch of schedule for many people across the globe and convenient - not numerically precise - alignment of solar cycle) are achieved.
I am pretty sure that 12=noon concept was largely independent on everyday life of most population back when it was used, as people worked sunrise to sunset in the field and whistle to whistle in most factories....

What you quoted was a reply to your comment about temperature, not time.

But anyway...  I have never suggested that our time spent awake should mirror the time the sun is up.  You seem to think I'm advocating that 12:00 be the middle of our waking hours, but that would be foolish.  To me, common sense is that people should wake up and start their day when the sun comes up–then those with shorter work schedules will perhaps have some leisure time while the daylight lasts, whereas those with longer work schedules probably won't.  And that reflects what you described about farmers (sunrise to sunset) and factory workers (16-hour shifts in the days before unions, although that may have required pre-dawn waking).  While dairy farmers do get up before dawn because dairy farming robs you of ALL leisure time (their last milking is also late at night), grain farmers don't typically hit the hay (pun not intended, but I'll go with it) as soon as the sun sets.  When the sun goes down, they come inside for supper and family time.  I believe people naturally fare better with pre-bedtime darkness than with post-waking darkness.

[kalvado]

I see what you did there, and I knew you'd do it, and it's not at all what I said.

What we are talking about is adjustment of general population daily schedule with respect to solar cycle. Clock is an instrument of synchronizing these individual schedules with each other and astronomy (sun position),  nothing more. 
Moreover, use of this tool did  change over time, from each city having its own time to time zones with uniform time to DST - all of these degrading your "solar noon at 12.01 PM" approach, but allowing better schedule synch and presumably convenient alignment of solar cycle to... lets call it business cycle of human life.
So I don't see anything wrong with further degradation of "solar noon sets clock" concept - as long as modern requirements to clock settings (synch of schedule for many people across the globe and convenient - not numerically precise - alignment of solar cycle) are achieved.
I am pretty sure that 12=noon concept was largely independent on everyday life of most population back when it was used, as people worked sunrise to sunset in the field and whistle to whistle in most factories....

What you quoted was a reply to your comment about temperature, not time.

But anyway...  I have never suggested that our time spent awake should mirror the time the sun is up.  You seem to think I'm advocating that 12:00 be the middle of our waking hours, but that would be foolish.  To me, common sense is that people should wake up and start their day when the sun comes up–then those with shorter work schedules will perhaps have some leisure time while the daylight lasts, whereas those with longer work schedules probably won't.  And that reflects what you described about farmers (sunrise to sunset) and factory workers (16-hour shifts in the days before unions, although that may have required pre-dawn waking).  While dairy farmers do get up before dawn because dairy farming robs you of ALL leisure time (their last milking is also late at night), grain farmers don't typically hit the hay (pun not intended, but I'll go with it) as soon as the sun sets.  When the sun goes down, they come inside for supper and family time.  I believe people naturally fare better with pre-bedtime darkness than with post-waking darkness.

I deleted last two lines before posting - I had a small rant that, unlike temperature, time of the day is a relative thing.

But anyway, we have 3 things to somehow align: sun (given by mother nature), clock (just a messenger - don't hit to hard) and a schedule your boss wants you to be available.
Your 21st century urban boss is acting, most likely, under assumption that while certain leeway may be possible, 8-5 with 1 hour brake is the well accepted default. Or something along those lines. Changing that perception is possible - and actually I advocate that upstream. But school districts are usually along same lines - sans leeway part.  They may look at the sun - but only as a secondary message. THis is not farming, where cows and corn don't care about numbers on the clock - this is an office decision.
That leaves clock as the easiest part to tune. And now it is not two clock arms pointing up, but school district published bus schedule what determines when the sun better be at the top of the curve. ANd my perception is that in this context solar noon at 1.30 PM is the best bet. Better than noon at 12.01 PM. At least that number is negotiable.

[kphoger]

8-5 with 1 hour brake is the well accepted default. Or something along those lines.

8 AM at the latest.  I hardly know anyone who starts work later than 8:00, but a LOT who start before that.  Assuming a start time of 8:00, a sunrise later than 7:00 (outside the dead of winter or northerly locations) should be avoided as it makes most people wake up before dawn.

[kalvado]

8-5 with 1 hour brake is the well accepted default. Or something along those lines.

8 AM at the latest.  I hardly know anyone who starts work later than 8:00, but a LOT who start before that.  Assuming a start time of 8:00, a sunrise later than 7:00 (outside the dead of winter or northerly locations) should be avoided as it makes most people wake up before dawn.

It doesn't change anything in a grand scheme of things,  Moreover, seems like a regional preference. And even then, local government may recommend stretch out starting times for different groups just to ease traffic problem.

[kphoger]

And even then, local government may recommend stretch out starting times for different groups just to ease traffic problem.

Wait, what?  The government is going to tell private companies what time their employees should start work?

[webny99]

A recent study analyzing 185,419 hospital contacts for unipolar depression found that there was a 11% increase in the incidence rate of unipolar depressive episodes during the transition from summer time to standard time.  Even as sunlight is shifted to the morning after the fall time change, there was a spike in depression (presumably because the sunset was suddenly an hour earlier... just as people are ready to relax after coming home from school/work it's already pitch dark out).  This study goes against conventional wisdom (IE. vdeane's responses).   

I'd be curious about comparing the last week of February/second week of October (which have similar daylight lengths, just offset about 40 minutes from each other due DST and the tilt of the Earth) as a way to compare typical conditions in each period in about as close to an apples to apples comparison as one can get.  That way the findings wouldn't be affected by the sudden jolt around DST.

Right; the underlying point here is that daylight is decreasing around the fall time change. I think that has a lot more to do with the increase in cases of depression than the supposed "lost hour". In other words, the likelihood of a case of depression is unrelated to how the daylight is assigned on the clock - it solely has to do with the total amount of daylight, which happens to be shrinking at its fastest rate in October. Therefore, cases of depression ought to be at a low in the spring and a high in the autumn, DST or no DST, so that data point can't really be used one way or the other.

[hotdogPi]

total amount of daylight, which happens to be shrinking at its fastest rate in October

September, actually. The amount of daylight change per day is greatest on the equinox.

[webny99]

total amount of daylight, which happens to be shrinking at its fastest rate in October

September, actually. The amount of daylight change per day is greatest on the equinox.

Right, but the shrinking is the most meaningful/noticeable in October, because the total is not only shrinking, it is also now adding up to less than 12 hours. That is to say, commutes and day to day activities that are done in daylight in August will also be done in daylight in September, even though daylight is being lost at a faster rate. Come October, and commutes and other morning/evening activities start happening in the dark.

[kalvado]

And even then, local government may recommend stretch out starting times for different groups just to ease traffic problem.

Wait, what?  The government is going to tell private companies what time their employees should start work?

At least here in NY that did happen. Large company wanted to realign 6 to 6 shift for some group of employers, but was told that it would place undue strain on traffic - and shift remained what it is.
I wouldn't be surprised if tax reduction (Payment In Leu Of Taxes = PILOT) agreements give local governments some leverage, and no larger business goes without one over here.
Incidentally, it is about roundabouts  unable to handle extra traffic during rush hour.