Most amateur astronomers have a love-hate relationship with the annual switch to and from "summer" time. One thing's for sure: Everyone has an opinion about it!

Some years ago, a local community organizer asked me to help her find some dates and times for family-friendly star parties over the summer. One problem, I said, is that here in Massachusetts the midsummer Sun doesn't set until after 8 p.m. and it doesn't get fully dark for at least another hour. It's challenging for young children to stay awake so late into the evening. "You can blame daylight-saving time," I told her.

Daylight time around the world
Most of the world's population doesn't switch back and forth to daylight-saving time.
J. Kelly Beatty

I don't know about you, but our annual switch to daylight time (called "summer time" most everywhere outside the U.S.) does amateur astronomy no favors. Most nights, by the time Sagittarius is up high enough to be seen well, I'm ready to put my head down for sleep.

Things were bad enough — "springing ahead" in April and "falling back" in October — but a few years ago Congress meddled further with Mother Nature when it passed the Energy Policy Act of 2005 and decreed that daylight-saving time would be extended, beginning in 2007. Now the U.S. observes summer time from the second Sunday of March until the first Sunday in November, which is about two-thirds of the year. Canada followed our lead, but European countries typically wait another three weeks to make the switch and Mexico another four.

In fact, although 70 countries (or parts of them) observe some form of summer time, it's mostly a high-latitude phenomenon. Most of the world's population avoids it altogether, and of course when northern countries are using it, our friends Down Under are not.

So how did all this come about in the first place? During his time as America's envoy to France, Benjamin Franklin once famously (but anonymously) wrote that Parisians could economize on candles by firing cannons at sunrise to get the populace on their feet sooner during summer.

But the tongue-in-cheek Franklin didn't propose changing clocks. For that, I blame golf.

This 1918 poster announces the adoption of Daylight Saving Time during World War I.
Wikimedia Commons

Let's turn back the clock to 1907, when Englishman William Willett published The Waste of Daylight. It seems that Willett, an avid golfer, wanted to spend more time after work perfecting his putting. So he proposed advancing the clock by 20 minutes in spring and fall and by 80 minutes in midsummer. His idea didn't take hold until World War I, when many nations briefly adopted daylight time to conserve energy. After that DST was off-again, on-again here in the U.S., making a comeback during World War II, until Congress made it permanent in 1966.

Remarkably, this time-honored practice has been, and continues to be, controversial. Arizona and Hawaii keep standard time year round; until recently most of Indiana did too. Farmers don't like it. Backyard astronomers don't like it. The date switch in 2007 cost an estimated $500 million to $1 billion. Twice-a-year clock shifts cause confusion, disrupt your sleep, and, according to multiple studies, even increase your risk of a stroke or heart attack.

DST Means Energy Savings — Not!

The usual justification for advancing the clock is energy savings. The logic here is that by having more daylight in the evening hours, we use less lighting. But in 1966, when DST became the law of the land, air conditioning wasn't nearly as pervasive as it is now.

At the request of Congress, the Department of Energy analyzed the effects of daylight time's extension in 2007 and concluded that there might be an energy saving of 0.5%. But other findings challenge that assessment. Some studies show that daylight time causes us to use more energy, because we run the AC longer in late afternoon during summer and need more heat on sunless spring and fall mornings.

In 2008, researchers Matthew Kotchen and Laura Grant (University of California, Santa Barbara) detailed what happened when Indiana caved in and adopted daylight-saving time in 2006. They find that Indianans' energy bills rose about 1% overall after the switch — and 2% to 4% in late summer and early fall. As Kotchen later concluded in a 2014 op-ed for the New York Times, "a growing body of evidence reveals that daylight saving time increases rather than decreases energy consumption."

Many countries used to observe Daylight Saving Time — but then thought better of it. It's rarely used in tropical countries, where the length of day and night are more consistently near 12 hours each throughout the year.
Wikimedia Commons

And more than a few countries — including Argentina, Iceland, Malaysia, Turkey, and even most of Canada's Saskatchewan (arguably as large as many countries) have switched to summer time year-round. Hey, who am I to argue with already flash-frozen Saskatchewanians who don't get to see sunrise in December until after 9 a.m.? Russia went to permanent DST in 2011 but then cried "Nyet!" and switched to permanent standard time three years later.

Closer to home, several states are toying with permanent summer time (in fact, last year Florida's legislature made it official by passing the "Sunshine Protection Act"). But while states can follow the lead of Hawai'i and Arizona, embracing standard time 24/7/52, it'd take an act of Congress to allow them to observe daylight-saving time year-round.

So the debate goes on. If Congress listened to me instead of those clock-watchers at the Department of Energy, we'd do away with this time-warp nonsense.

This post originally appeared in 2009 and has been updated with recent policy events and scientific research. See the excellent article in Wikipedia for more information on Daylight Saving Time.


Image of Eric F. Diaz

Eric F. Diaz

March 19, 2009 at 6:28 pm

I'm with you, Kelly! This daylight-savings time is nothing but a useless royal pain! Until I read this blog, I thought I was the only one that felt that way. I can't tell you how gratifying it is to hear that you as well as many others feel the same way.

I sincerely hope that you can get the ear of the President if the White House star party does indeed take place.

Clear skies,


You must be logged in to post a comment.

Image of Johannes-Nordvall


March 10, 2019 at 3:11 am

Yes here in northern Sweden we can see no stars with daylight saving time and if they now adopt it year around it is end for amateur astronomy

You must be logged in to post a comment.

Image of Grant Miller

Grant Miller

March 19, 2009 at 7:30 pm

I hate DST, too. Just think of all the time and money that is wasted just changing all the clocks twice every year. Not to mention that it confuses my children into thinking that their bedtime has shifted, "but it's still light outside Daddy". Law enforcement, the military, hospitals, and others also have to deal with the confusion of keeping and recording "accurate" time records when the clocks suddenly shift an hour.
I wish you the best of luck with the President, but I fear we have a long way to go in convincing the majority of the rest of the public that DST should be discontinued.

You must be logged in to post a comment.

Image of tom-dasilva


March 12, 2019 at 6:47 pm

Yep. In control law design, a hard switch without synchronizing integrators causes a transient response. So it is with the human being.

You must be logged in to post a comment.

Image of Joseph


March 19, 2009 at 10:52 pm

I believe I probably have one the best schedules. I am a chef, so we are talking afternoons and evenings. I can not think of a better way to relax.

You must be logged in to post a comment.

Image of Daniel Kunimura

Daniel Kunimura

March 20, 2009 at 7:35 am

Studies have also shown that another repercussion of increasing the length of daylight savings time (in America, anyway) is that with the increase of daylight hours people will tend to spend more time on the road in their vehicles which increase fuel consumption and carbon based emissions.

You must be logged in to post a comment.

Image of Gerald Hanner

Gerald Hanner

March 20, 2009 at 9:04 am

Your map of the USA omits the fact that both Hawai'i and Alaska don't participate in DST. The reasons should be obvious. For the rest of the continental 48, DST is an act of supreme stupidity and exacerbated by the clown show that is the US Congress.

Enacting DST as an energy saver is the ultimate act of futility; enacting DST so that it covers the period between the autumnal equinox and the spring equinox ignores the fact that there are more hours of darkness than daylight during those months. There is no daylight to "save." In the late 20th/early 21st centuries, we routinely turn night into day. We operate 24/7. There is a growing concern that light pollution is taking away our ability to conduct astronomy. Many workers nowadays have the option of "flex time;" they can control their working/leisure hours to suit themselves.

Face facts: Moving the clocks forward an hour in late winter only gets working people up an hour earlier. They still go to work in the dark, or at best, in the early morning twilight. DST is an anachronism and meaningless in modern US culture.

You must be logged in to post a comment.

Image of Fred H

Fred H

March 20, 2009 at 10:12 am

I understand that there is a possible push to make DST permanent and extend it another hour to 2 hours total. Keep in mind, this is only a rumor. Anyone know the truth here?

You must be logged in to post a comment.

Image of Bruce


March 20, 2009 at 10:45 am

One of the big reasons Indiana balked for so many years is because we're on the western edge of the eastern time zone. For all practical purposes, we've been observing daylight savings time year-'round. Since conversion in 2007 I've driven to work in the dark more times than I care to count. And astronomy? In late June and early July it doesn't get dark until 11 PM. I'm not kidding.
I feel for your astronomy situation in Boston but it's NOTHING compared to the fiasco that occurred here. I blame our governor (Mitch Daniels) for it.

You must be logged in to post a comment.

Image of John Collins

John Collins

March 20, 2009 at 10:47 am

When I was a child, I learned from my learned relatives that DST had nothing to do with saving energy or using more fuel, etc.
It had to do with farming. Farmers had (have) lots of work to do in the summer time. When it is light at 5 AM ST, farmers are in still bed sleeping and losing good daylight time. By changing that 5AM to 6AM (DST), farm prople are getting just up allowing that extra daylight time for farm work.

Regards to all,


You must be logged in to post a comment.

Image of redshiftbaron


March 11, 2019 at 9:12 am

I heard the opposite: farmers have to get up with the sun because the cows don't care about DST! They can get up at any time they like anyway, no need to change the clocks!
I worked with time standards for years and when I asked people 'why DST?' most answers were to have longer evenings for their evening walk, more BBQ time, their favorite sport (including golf), etc. It has nothing to do with saving energy.
The sooner we can get rid of that ridiculous cultural anachronism, the better! Good point of view Kelly!

You must be logged in to post a comment.

Image of Ptoe


March 20, 2009 at 11:07 am

I despise it! Always have. Truly messes with my circadian rhythm! And now that I am a budding Amateur Astronomer I have one more reason!
wish we could all get together and VETO it!
Fat Chance.
Love your column.

You must be logged in to post a comment.

Image of John


March 20, 2009 at 12:42 pm

Got GREAT idea. Since the sun rises a half hour later here in Ohio than it does at the brain trust (that's Wash. D.C), Ohio's DST should 1.5hrs and not 1.0. Eastern Indiana could be 1.75hrs, etc. That makes about as much sense as 8 months of DST.

You must be logged in to post a comment.

Image of Brian Halls

Brian Halls

March 21, 2009 at 1:41 am

Or summer time as it is called here in the UK has similar problems to you guys in the US. There was - during the 1970's - a brief time when the UK flirted with British Standard Time for several years (GMT + 1hr. But it flopped. Now our own Parliament want to bring it back - not sure if that is for golfing reasons or they want more daylight with which to count their loot!

On top of that, the European Union wish to have a standard time zone across the Community; great if the world was flat but it isn't. Imagine during the winter the Sun rising in Greece at 8 a.m. but the Sun would not rise in Ireland until 11 a.m.

Time is an area which politicians should leave well alone!

You must be logged in to post a comment.

Image of Gene Dees

Gene Dees

March 21, 2009 at 2:25 am

I loved the comment about the farmers sleeping well past sunrise because the clock said it was too early to get up! Farmers have always worked by the Sun, not clocks. And any farmer who sleeps in because his clock said so deserves to lose money. When I could still work, it simply felt good to have daylight to drive home in and daylight to enjoy my life as opposed to going to work in the dark and driving home in the dark. In the depths of winter the "studies" we see are homing in on how a lack of sunlight negatively affects humans. Maybe that's one of the bugaboos you get stuck with living at higher latitudes ... but then, come spring and summer, you don't really need DST. All the houses have shutters on them and they aren't for looks. You need them unless you want to get fried out of bed at 4 AM. Meanwhile, let me keep my DST. I enjoy it and it helps keep me sane. And, it really isn't all that hard to adjust to the hour's difference ... and concerning the comment that, by the time Sagitarius is rising, the commenter is just putting his head down to sleep ... say what? Does your clock really rule your life like that? Get some help and leave DST alone. Allowing yourself to get that worked up is going to mess with your sleep far more than DST ever will.

You must be logged in to post a comment.

Image of Milton


March 21, 2009 at 7:14 am

We finally voted it in for good in 1978 and I have hated it ever since. When the changes occurs, it causes severe disruption in the daily schedule, there is the hassle of changing timepieces (5 for me) and it is extremely inconvenient for astronomical observing in the evening. I don't ever recall a time when the extra daylight was useful.
For example:
June 21, 2009
The lat, lon my area is 42 16, -83 23. The lat, lon of the westernmost point in MI still in the eastern time zone is 46 45 56, -89 53 14.
ast naut civ rise trans set civ naut ast
my area 3:43 4:37 5:22 5:57 13:35 21:14 21:48 22:33 23:28
west MI 3:12 4:32 5:26 6:05 14:01 21:57 22:37 23:31 00:50

How to get rid of it?

You must be logged in to post a comment.

Image of Frank Cernik

Frank Cernik

March 21, 2009 at 11:01 am

I suppose Congress could do worse; and try to legislate every day to be 16 hours of daylight, sunny & 72 degreesF. and to have it only rain at night when no one would care about not getting a tan. After all, didn't they once try to legislate PI as exactly 3.0?
Be thankful they can't legislate physical laws (YET).

You must be logged in to post a comment.

Image of Al Wilson

Al Wilson

March 21, 2009 at 4:10 pm

No DST, and the best skies of any state! Why aren't you guys living here? 😉

You must be logged in to post a comment.

Image of Geoff Gaherty

Geoff Gaherty

March 21, 2009 at 4:21 pm

I've just been asked by a teacher to organize the telescopes for a star party in late April. She suggested that the party take place from 8 pm to 10 pm. Now I have to tell her (as I've had to do with so many teachers) that it won't get fully dark that night in my location until 10:07 pm!

The other people who suffer are the rural kids who have to go to school in the dark. It just started to get light when I get up two weeks ago, when they bumped the clocks forward an hour, and now I'm getting up in the dark again.

You must be logged in to post a comment.

Image of Jim


March 21, 2009 at 8:02 pm

I am in Western OH, longitude approx 83 deg 35 min. The mid point between EST and CST meridian would be 82 30, so actually I should be in the Central time zone. I need to FALL BACK in summer! Compounding the problem is DST, so we are "off" by TWO HOURS in summer. It's not dark until 11 p.m. in June/July.

You must be logged in to post a comment.

Image of Jose Agustoni

Jose Agustoni

March 22, 2009 at 6:43 pm

I think the US, as a country that extends from east to west, don't have a problem as Brazil (where I live). In Brazil we have a north to south concentration of big cities and the bigger energy demand. So our problem is to flat down the high demand curve of energy at the end of the afternoon. With DST we achieve this by letting the industry and offices to switch off their machines and air-conditioners before the residences turn on theirs lights and electric equipments.
I use to say that DST is not to make economy, but to flatten the high demand, even if this do not bring economy of energy.

Regards from Brazil,

You must be logged in to post a comment.

Image of Justin S

Justin S

March 23, 2009 at 11:39 am

What ever happened to the concept that the sun is supposed to cross the meridian at noon? Sure time zones meddled with that but at least ie was fairly close.

You must be logged in to post a comment.

Image of Pete Jackson

Pete Jackson

March 25, 2009 at 9:02 am

When we were recently in Australia, in a region that doesn't observe DST, and it was summer in the southern hemisphere, it became really clear that a lot of daylight was being wasted; the hotel didn't start breakfast till 7AM so much of the best, coolest part of the day was gone by the time one would leave the hotel.

So, it became clear that if there were no DST, there would be an enormous clamor by employees of various firms to switch working hours forward during the summer to avoid wasting this daylight. Also, contractors would want to start outside work at 6 AM to avoid missing the best part of the working day.

And recreational facilities like golf courses and theme parks would be besieging congress big time to bring back DST.

Hence, without DST, there would be an enormous confusion as many employers, contractors and other entities would switch their times back and forth during the year, and all at their own dates. A uniform DST, while annoying, makes all the changes happen at the same time.

That said, it was really stupid to make the USA switch early in March, causing the sun to rise later in March than it does in January!

You must be logged in to post a comment.

Image of John Rombi

John Rombi

March 27, 2009 at 4:14 am

With the adjustment of the clocks, we humans are exposed to more hours of potential harmful sunlight.
Here in Australia (the melanoma capitol of the world)our governments are spending millions of dollars telling us the dangers of the Sun (especially in Summer)
But what has our state government done last year? Extend DST by one month at the beginning and one week at the end!!!

You must be logged in to post a comment.

Image of bob kelly

bob kelly

March 27, 2009 at 5:19 am

I agree with your point about the difficulties of doing star parties in the summer - even here in the NYC area, it's late when it gets dark!
However, take a closer look at some of the data you refer to. The DOE study only covered the energy savings of EXTENDING DST 3 weeks in the spring and one week in the fall, not the total energy savings from moving to DST. So, it's not surprising that the energy savings are small when compared to annual energy consumption.
The results of Kotchen and Grant's study are not very surprising, since Indiana is very far west in the Eastern Time Zone and already has a late sunrise in the summer, even without Daylight Time. So Indiana is an extreme case where the usefulness of DST is not a large as more easterly locations in the Eastern Zone. If the authors could not prove that DST's benefits were small or negative in Indiana, they have no hope of proving their thesis in states further east. It's understandable they would start with Indiana, but the implication that these findings are indicative of the (lack of) effectiveness of DST in general is misleading.
A 4:30 summer sunrise in NYC is wasted light. I even look forward to the time change in the spring, so I can get an early morning look at the sky - Jupiter is great to see hanging over the eastern horizon and with the moon nearby - just a great sight!
However, I really do understand if other people don't share my excitement!

You must be logged in to post a comment.

Image of Peter Wilson

Peter Wilson

March 27, 2009 at 7:34 am

If there's a reason to start earlier when there's more daylight, then change your schedule, as farmers and construction workers do in Arizona. But don't change the clock! Changing the clock is like using Centigrade in the summer to save on air-conditioning, and Farenheit in the winter to save on heating!

You must be logged in to post a comment.

Image of Greg Simpson

Greg Simpson

March 28, 2009 at 4:46 am

Yeah, it's great having even MORE hours of daylight in the summer, here in broiling Florida! It's brutally hot and humid here anyway, and the extra daytime added each year is nonsensical. Also, as we're experiencing right now, sunrise isn't until about 7:30, which means, among other things, schoolchildren have to make their way to the school bus stop in the dark!
Also, I have to agree with Mr. Hanner: We're a round-the-clock culture now, with flex-time, mid-shift and late-shift workers. The 9 to 5 work schedule is rapidly becoming a thing of the past--as should DST!

You must be logged in to post a comment.

Image of Malcolm McClintick

Malcolm McClintick

June 15, 2009 at 9:28 am

DST is absurd for all the reasons everyone else has given -- always getting up in the dark, never seeing the stars, wasting energy, etc. But here in Indiana there's an extra problem. Since the sun doesn't set until after 9 p.m. and it's still light outside until at least 10 p.m., all the local fireworks fanatics "wait until dark" to start shooting off the biggest, loudest, most obnoxious fireworks money can buy (thanks, Governor Daniels). So for the weeks before and after July 4, I'm kept awake until one or two a.m. by continuous deafening explosions.

You must be logged in to post a comment.

Image of marqthompson


March 29, 2010 at 2:10 am

This is a wonderful article. The things given are unanimous and needs to be appreciated by everyone.
National Savings Premium Bonds

You must be logged in to post a comment.

Image of Astronomer


October 31, 2010 at 1:09 pm

I hate DST. I don't think we have the authority to mess up the time. It's so inconvenient to add or subtract an hour when you're looking at star charts. And it doesn't help anything; it doesn't change the amount of time that the Sun is up.
What I've been trying to figure out is, "What is the original time? Did we add DST or was it the original time?" I would really like to know.

You must be logged in to post a comment.

Image of Leah


March 14, 2011 at 3:31 pm

I agree with the article. There are so many downfalls to DST, and no reasons to practice it; I (and many others) believe that it should be stopped. I actually don't practice it myself; I never change my clocks or watches. However, it still means that I have to subtract an hour off of all events (except for astronomical ones). I live in Ohio, and I'm writing to all the state representatives asking for it to be stopped. I encourage you to do the same - let's stop this superfluous, time-warping system!

You must be logged in to post a comment.

Image of Anthony Barreiro

Anthony Barreiro

March 10, 2019 at 7:21 pm

In November 2018 Californians (mistakenly) approved a ballot initiative to establish year-round daylight saving time. The most persuasive argument was that people don't want to keep changing the clocks twice a year. Both the state legislature and the federal congress would still need to pass laws to allow California to observe year-round DST.

The simplest and best solution would be for California to follow Arizona's lead and stay on standard time all year. The state legislature could make that decision without needing Congress to agree. In the summer, government offices, schools, and businesses could open and close an hour earlier than in the winter. We don't need to change the clocks to get up earlier in the summer.

You must be logged in to post a comment.

Image of Russell Sampson

Russell Sampson

March 10, 2019 at 10:01 pm

Kelly: As an ex-pat Canadian I have to point out that the extensively agricultural province of Saskatchewan does NOT observe daylight savings time.

You must be logged in to post a comment.

You must be logged in to post a comment.