I’ve been a civil time geek for a while, and I follow an e-mail list relating to IANA’s tz database. It looks like the tz-art.html file in the next release will contain a link to Wednesday’s xkcd. 😎
There’s been a lot of discussion on the list about the proposed “permanent daylight saving time” law that just passed in the U.S. House of Representatives. It sounds simple: the proposed law doesn’t change the time zone names; it just changes the offsets from UTC and makes them permanent. For example, “eastern standard time” would become UTC−4:00 year-round. But states would be allowed to opt out, so for example, Hawaii could keep its UTC−10:00.
So what if Arizona decides to keep its UTC−7:00 year-round but doesn’t call it Pacific standard time? Mountain standard time would mean different things in tz’s time zones, America/Phoenix (Arizona except Navajo Nation) and America/Denver (generic mountain time).
Furthermore, it turns out that there’s lots of legacy code out there that hard-codes offsets to abbreviations like “MST”. All that code happens to work at present; but it’s been wrong for decades and so will likely stay wrong.
I’ll bring the popcorn. 😎
The the People’s Republic of China has just one “time zone”.
Is that what the USA is heading for?
I don’t know how silly it is – I don’t mind clock-changing that much, but there are some distinct upsides to making summer time permanent. Also, while I live in Canada, I know that our governments will follow the USA in whatever they decide on this issue, so…Congress is effectively deciding for 2 countries. Anyway, I’ve given it a lot of thought, and for me, permanent summer/daylight time makes WAY more sense than permanent standard time. I have VERY strong feelings on this issue, as you will no doubt intuit from the length of this comment!
In my city of Winnipeg, MB, we have under 9 daily hours with the sun above the horizon between the 16th of November and the 25th of January (the solstice has a low of 8 hours and 5 minutes, FYI). It is VERY important to get sunlight in the winter, but very few people actually do, due to their schedules (which are usually dictated by their employment situation). I swear more than half of the people here are vitamin D deficient (including myself – I take supplements because I tested a 38 nmol/L back in January…the lowest acceptable value of the “normal” range, according to endocrine experts, is 75 nmol/L, and mine was like, half of that).
The problem for me (and a LOT of people like me, people who are arriving at work at ~7:30 AM, and who leave work at ~4:30 PM) is that under standard time, there is a period, from November 20th to January 2nd where I go to work before sunrise, and leave after sunset. That is 7 weeks where I won’t see the sun on any weekday. It is terrible for my health [aside: it is no doubt responsible for all of that vitamin D deficiency]. The sun is a mere RUMOUR for me at this time…I work in a dark, windowless room (which I generally enjoy, most of the time), but we are not evolved for such conditions, and my health (including mental health) suffers.
Changing to permanent summer time wouldn’t affect me at all in the morning (I’m already at work before sunrise between November 10th and February 19th, which are dates that are currently ALL on standard time anyway so I know what that feels like…moving to summer time would just push sunrise an hour later, but I’m indoors regardless, so whatever). While I do accept the idea that all of the doctors are yelling about, that “morning sun is really important for our circadian cycle,” for that 10 week period, regardless of the standard/summer time variable, I won’t get ANY morning sun on weekdays. However, SOME sun is better than no sun at all. Moving to summer time throughout the winter (no “fall back”) would guarantee AFTERNOON sun exposure. Instead of 7 weeks without seeing the sun, it would be ZERO weeks (and the minimum sun exposure would be 45 minutes a day, which is not insignificant).To me, that is an actual BENEFIT to permanent summer time. And if we’re going to eliminate the clock change, the new system better have some benefits (otherwise why bother?).
Moving to permanent standard time has NO major benefits that I can tell (when compared to the status quo of daylight saving). You’re not solving the winter sun exposure problem for me (and for people like me…I estimate ~35-40% of adults with full-time jobs are in a similar situation to me, given that in my experience most day-shift healthcare workers, tradespeople, office workers, lots of people in the service industry and even teachers are arriving at work between 7:30 and 8 AM, and leaving at 4:30 PM…or later). There is a *possible* benefit in that it’s not a daylight saving system, so there is no clock-switching (which has some potential negative health effects, most of which are only significant at the population level…the VAST majority of individuals’ health is not impacted in the slightest). However, to pay for that one possibly-helpful thing (which is also available to us on permanent summer time, btw), we have to suffer the significant drawback of significantly less light in the evenings – on permanent standard time, an earlier sunset would adversely affect all kinds of recreational activities people do between supper and bedtime (the latest sunset would be 8:40 PM, whereas on summer time it’s 9:40 PM). Unfortunately, summers here are all too brief, and you want to enjoy every minute of them. But having the sun rise before 6 AM starting on April 3rd, and before 5 AM starting on May 4th (June 10th would be the earliest sunrise on permanent standard time: 4:20 AM) is WASTING considerable sun-up time since almost nobody will be enjoying it! And the pre-5 AM sunrises would continue until August 3rd, while the pre-6 AM ones would end on September 13th. That’s ~5.5 months of pre-6 AM sunrises, amounting to a waste of 167 hours of sun-up time before 6 AM, when ~90% of people will not be awake, time that has been stolen from the evenings when EVERYONE can enjoy it.
Anyway, I did the math – permanent summer time would more than DOUBLE my personal weekday sun exposure from November 1st thru February 28th (theoretical sun exposure I guess…clouds can obviously interfere with the intensity of the sunlight), when compared to standard time. And on an annual basis, permanent summer time would give me 10% more sunlight exposure (for my waking hours) than permanent standard time, and 9% more than the status quo of daylight saving. Like I said, I have STRONG feelings about this. If we’re making this change, we need to make summer/daylight time permanent. Making standard time permanent is nonsensical.
The Earth is not flat.
The only way that doing “permanent summer time” or “permanent winter time” is if the earth is flat.
The Earth is not flat.
Yeah, but time is arbitrary.
I used to live in a place with daylight savings, now I live in a place without.
Basically, it’s slavery to the clock. You know?
Nothing stopping people getting up whenever or going to bed whenever, other than work and assigned times.
Hours of shop openings, that sort of thing.
Changing now, in this the 2nd quarter of C21/
Time is not arbitrary.
Measurement of time is arbitrary.
If Putin wants his own popcorn, his next conversation with Trump could casually mention that daylight is good for grass. Nowhere more so than golf courses in fact, and that nearly doubling the portion of the year spent saving American daylight will make Trump’s game even more awesome.
The proposed law would be sure to pass.
@2 VolcanoMan
By your rationale, having an offset of one hour is good. Wouldn’t having an offset of two hours be better? What about three?
Standard time makes sense in those meridians where mean 24-hour noon and apparent solar noon coincide at least once per year. (It makes decidedly less sense in places like Arizona where they chose the wrong time zone — it should have been UTC-7h30m).
I for one don’t mind changing the clocks forward and back — I kind of enjoy it. Sure, you can make the point that DST is directly responsible for significant excess death during switchovers, but I find offering tribute to a violent god to be that much more thrilling. Daylight saving demands sacrifice!
The problem is there are always winners and losers no matter which you choose. Like Volcano Man, I would prefer permanent daylight time. When they did that in the 70s, it was so unpopular that it was quickly reversed. I do like the idea of letting each state decide it on their own. Michigan and Massachusetts, on opposite sides of the Eastern time zone, may have very different ideas about what the optimal time zone is, and whether daylight, standard, or switching between the two makes the most sense.
Instead of morning lasting until 12:59 in Summer, why not keep midday at 12:00 all year round, and just open for business earlier in Summer instead of pretending it’s an hour later than what it really is?
bluerizlagirl . @9:
I’m imagining 21,600 time zones, one for each minute of longitude. The width would vary withlatitude. 😎 (I’m pretty sure that that’s not what you meant, but it’s amusing to contemplate.)
Civil time is a cultural thing, not a physical thing. The time of day is whatever most folks want it to be. I have no opinion on that and, honestly, don’t really care. I’m happy to go with the flow.
The arguments about the “permanent daylight saving time” law, and most of the comments on this post, are all about whether standard time or daylight saving time should be preferred; but the point of my post was that there are technical problems of which most folks are unaware, and I pointed out a couple of simple ones. A more serious issue is the amount of time, sometimes many months, that it takes for changes to percolate down through various levels of software before the change appears on your phone. If the U.S. gets rid of the time changes, regardless of which way it goes, I anticipate lots of confusion for a while after the change is adopted. (And note that Canada and Mexico will probably have to pick up behind the elephant in the room.)
@9 bluerizz
Earth’s orbit is elliptical, you’ll run into problems making the necessary adjustments for that system. For more information, see the Equation of time [Wikipedia].
tl;dr, you can have apparent solar time, but you lose the benefits of each day being the same number of SI seconds in length, and also having other people agree with you about what time it is.