A handful of politicians seek to extend Daylight Saving Time (DST) to the full year. Biannual clock-switching is harmful, but year-round DST is worse, even deadly.

Year-round Standard Time instead would save lives, improve physical and mental health, reduce pollution, slow global warming, save money, and prove more popular. It’s for good reason that year-round DST has long been discouraged by law. Legislate by data, not anecdote.

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Public Health

Both the change of clocks to DST and the continual observation of DST are lethal to human health.

The abrupt move forward in springtime by one hour is well-known for its shock to body and mind — causing traffic deaths, workplace accidents, lost productivity, and hospitalizations. Incidence of stroke increases 9% upon switching to DST in spring. Incidence of heart attack increases 24 to 50% after switching to DST, and it decreases 21% after returning to Standard Time in autumn. These acute effects persist for four days after switching clocks forward.

Circadian biologists have also found that remaining on DST causes continual harm — that we never fully adjust to DST, we merely sleep less long and less well than we need.

Healthful sleep is necessary for prosperity and longevity, and it’s biologically regulated by melatonin and cortisol. The body’s natural release of these sleeping and waking hormones is tuned to the setting and rising of the sun. DST postpones both sunset and sunrise on our social clock, which disrupts the body’s hormone balance, and leads people both to stay awake late and to feel a need to sleep late. However, social schedules demand we wake on time regardless of how we feel, and year-round DST would demand we wake before sunrise for roughly half of the year.

DST’s combination of late daylight and pre-sunrise waking robs us of 19 minutes of sleep every night on average. Cortisol rhythms advance only two minutes despite clocks being advanced 60 minutes under DST. This creates a “social jet lag”, which is far worse for health than ordinary jet lag, and which never is relieved under year-round DST. The body attempts to compensate by sleeping late on non–work days, but the benefits of sleep can’t be stored.

DST’s chronic lack of sleep increases risks of heart disease, stroke, diabetes, cancer, epileptic seizures, high blood pressure, obesity, metabolic disorders, personality disorders, unintentional midday sleep, caffeine abuse, alcohol abuse, depression, and suicidality. It harms cognition, productivity, reaction time, stress management, and life expectancy, in both children and adults. Delaying sunset and sunrise by one hour increases breast and prostate cancer rates by up to 12%, lung and colorectal cancer 14%, liver cancer 21%, stomach cancer 27%, uterine cancer 30%, leukemia 36%, and esophageal cancer 48%. Seasonal depression is more prevalent at northerly latitudes (10% of Seattle, 25% of Alaska), where winter days are unavoidably shorter. This suffering is most effectively relieved by adding light to mornings — not evenings.

Some claim DST may increase exercise. However, the study to back this claim only considered regions that observe summer DST (ignoring those on year-round Standard Time), its gains averaged just two minutes per day (not the full hour the clock gets advanced), and these small gains were seen only in Europe and Australia (with no gains in America). Another study that did compare close regions with different time observations found no increase or decrease in exercise. Furthermore, evening exercise can disrupt sleep, and lack of sleep can increase sports injuries by 70%.

The Center for Circadian Biology, the Society for Research on Biological Rhythms, the European Biological Rhythms Society, and the European Sleep Research Society have all opposed year-round DST and endorsed year-round Standard Time, citing its continual disruption to sleep cycles and long-term harm to health, safety, environment, and economy.

References below, and with quotations on our website.

Public Safety

DST kills commuting children and adults, whether we observe it seasonally or year-round.

The springtime switch to DST shocks the human circadian system with a sudden loss of 40 minutes of sleep on average. This disruption negatively affects reaction times, which causes traffic deaths in the US to spike 17% the Monday after switching to DST. The increase in road deaths persists at 5.6% the remaining week after switching. The lives of up to 195 motorists and 171 pedestrians are lost due to ”springing forward” each year.

Furthermore, year-round DST would force us to begin work or school before sunrise for roughly half of the year. Mornings are the worst time for dark commutes, when grogginess from lack of sleep (19 minutes lost every night under DST) is strongest for walking or busing children, inexperienced teen drivers, and driving adults alike. Motor vehicle accidents are the primary cause of accidental death in the US. 70% of all US pedestrian deaths occur under darkness, and 20% of all US pedestrians killed are children. In 1974, eight kids died on dark winter mornings in just one month of year-round DST in Florida.

The National Education Association, the American Federation of Teachers, the National School Boards Association, and the National PTA have all opposed year-round DST, citing children’s safety.

References below, and with quotations on our website.

Energy & Environment

DST wastes energy and increases pollution. Stealing an hour of daylight from mornings to add to evenings might reduce evening lighting costs as originally promised, but it’s offset by increased morning lighting, and lighting is no longer a considerable energy expense. Instead, DST increases demand both for morning heat (since it wakes us before sunrise) and evening air conditioning (since it keeps us awake when solar build-up is strongest). DST also encourages more evening driving, leading the petroleum and retail industries to become major lobbies for extensions of DST. These increases to heating, air conditioning, and driving all increase energy costs, pollution, and global warming. It’s a chief reason why Arizona observes year-round Standard Time.

When Indiana switched from year-round Standard Time to summertime DST in 2007, annual consumer electricity demand rose 1 to 4%. This jump cost residents an extra $9M per year in utilities, and up to $5.5M annually in added pollution expenses. The same effect was seen in Sydney, Australia, when DST was extended for the 2000 Summer Olympics. Energy waste could be even worse in regions with greater populations or more extreme weather.

References below, and with quotations on our website.


Both switching to DST and remaining on DST have high economic costs, which manifest as stock-market disruption, lost productivity, workplace injuries, healthcare expenses, and overall lower earnings.

Workplace injuries in US laborers increase 5.7% in the days after moving clocks forward in spring, due to the sudden loss of an average of 40 minutes of sleep. Injuries increase in severity too, resulting in 67% more days lost after switching clocks forward. US office productivity drops 20% after springtime switching, for a loss of $434M annually nationwide. Stocks drop 200 to 500% more than usual the Monday after moving clocks forward to DST, at a cost of $31B in the US. These injuries, missed days, lost productivity, and stock losses don’t reoccur in the autumn return to Standard Time, nor are they ever recouped.

Economic losses continue under DST beyond the springtime clock switch, as seen in data from western and eastern edges of time zones, where sunsets and sunrises naturally differ by an hour. One added hour of sunlight in evenings and its corresponding lost hour in mornings reduce sleep duration by an average of 19 minutes nightly. This continual loss of sleep every night manifests as health problems (at a cost of $2.35B annually in the US), as lost productivity (totaling 4.4M lost work days, at a cost of $613M annually nationwide), and even as lower earnings (3.0 to 4.9% less than in neighboring counties with a one-hour earlier sunset and sunrise). An increase in average nightly sleep by a full hour can increase earnings by the same amount as half a year of added education would, and it can increase productivity more than an entire year of added education.

References below, and with quotations on our website.

Religious Freedom

DST disrupts religious communities. Judaism, for example, calls for morning prayers at sunrise, which would unfairly overlap with work hours under year-round DST. Agudath Israel of America, Agudath Israel of California, Agudath Israel of Florida, the Rabbinical Council of America, the Rabbinical Council of California, and Adath Israel of San Francisco have all opposed year-round DST and endorsed year-round Standard Time.

References below, and with quotations on our website.

Late Sunrises

Year-round DST makes sunrises too late. Under year-round DST, sunrise would be as late as 8:44am in California, 8:56am in Texas, 8:46am in New York, 9:01am in Ohio, 8:40am in North Carolina, 9:33am in Michigan, and 9:44am in the contiguous US.

Sunrises after 8am DST would last as many as 15 weeks (3.5 months) in California, 20 weeks (4.7 months) in Texas, 15 weeks (3.5 months) in New York, 19 weeks (4.3 months) in Ohio, 16 weeks (3.7 months) in North Carolina, 22 weeks (5.2 months) in Michigan, and 24 weeks (5.4 months) in the contiguous US.

References below, and with quotations on our website.

Public Opinion

No survey has shown definitively which time the populace prefers. Most people don’t know which time is which (granted, it can be confusing). Preference between the two times is rarely asked, and polls depend heavily on how and when they’re conducted. Many people think they prefer DST, but they usually just prefer summer’s naturally longer days, without realizing how dark winter mornings would be under year-round DST.

Those who favor one time or the other are generally split (35% DST vs 28% Standard in a 2019 March poll of 1,288 Americans; 47% Standard vs 41% DST in a 2019 February poll of 1,030 Seattleites).

The majority clearly wish to stop switching clocks as soon as possible (84% in a 2018 poll of 4.6M Europeans; 67% in a 2018 poll of 600 Pacific Northwesterners; 60% in California’s 2018 Prop 7 ballot measure; 54% in a 2019 poll of 1,288 Americans).

History has shown when public opinion favors year-round DST before enactment, support quickly reverses to opposition after DST’s long, dark winter mornings are experienced (as happened in the UK in 1971, the US in 1974, and Russia in 2014).

Public opinion demands we stop switching clocks now. The quickest, easiest, safest way is to restore year-round Standard Time. Moreover, public health demands we both stop switching clocks now and choose year-round Standard Time. Public health must take precedence over shifting public opinion of the two times.

References below, and with quotations on our website.

Learn from History

The US tried year-round DST in 1974. While initially supported by an estimated 79% of the population, its popularity quickly plummeted to 42% after its first winter. Several children died on their way to school, the public bemoaned the unnaturally late, dark mornings, and the two-year experiment was ended a year and a half early.

Year-round DST was similarly tried in the UK from 1968 to 1971, and in Russia from 2011 to 2014. Each time, the program was greeted with initial optimism, followed by public outcry and reversal.

References below, and with quotations on our website.

Objective Reality

No bill can make winter’s daylight as long as summer’s daylight. DST is mistakenly associated with summer’s naturally longer days, but summer days will still be just as long under year-round Standard Time as they were under DST.

DST is akin to “vanity sizing”, wherein clothiers arbitrarily assign different numbers to the same sizes to make consumers feel thinner. DST’s arbitrarily added hour falsely makes some people feel they have more daylight. We could add six hours to the clock to keep sun up until a false midnight, but it would then be dark until the false noon.

DST also leads to an unsustainable “arms race”. We push the clock forward for more after-work daylight, then we push start times forward for more pre-work rest, which cancels the after-work daylight. Calls have already begun to delay work hours until 10am DST (which is only 9am Standard). The benefits of starting school later would also be canceled by year-round DST (and helped by year-round Standard Time).

Standard Time is the most practical model for timekeeping that is based in objective reality. It’s an approximation of solar time, which is itself a geometric measurement of nature. Twelve noon corresponds to the sun’s highest point in the sky; twelve midnight corresponds to the darkest point of night. Twelve was chosen for its even fractions (half, third, quarter).

Standard Time facilitates many simple estimations: time of day from the sun’s position, time of night from the moon or stars, time of sunrise or sunset, time zone differences, latitude on earth, sunburn hours… This knowledge — this connection to nature — is needlessly obscured under Daylight Saving.

References below, and with quotations on our website.

Simplest Solution

The simplest way to end clock changes is to restore year-round Standard Time. Year-round Standard Time could end clock switches in mere months, with no need for Federal action. Arizona, Hawaii, and all US territories did this long ago, and no complaints have been heard since.

The pursuit instead for year-round DST would require sweeping change to Federal law by Congress — which would take several years, which might never occur, or which might be changed then reverted (as happened in 1974). Year-round DST defies the people’s will for an immediate end to clock switches; it’s a waste of legislative time and taxpayer money.

A return instead to year-round Standard Time would cost nothing and could be enacted this year. It would benefit public health, public safety, the environment, the economy — and it would be an easy win for lawmakers.

References below, and with quotations on our website.

Save Standard Time is wholly a grassroots, volunteer effort, founded by a software engineer, amateur astronomer, and conservationist, in California.

Visit our website and follow us on Twitter and Facebook to see how you can help take action to save Standard Time.

🌞 SaveStandardTime.com

🌞 Twitter.com/SaveStandard

🌞 Facebook.com/SaveStandard

References with quotations and links to support all claims are documented in full on our website.

References: Public Health

Ackerman, Ximei; Phan, Tiffany; Landaverde, Maryanna Sophia; Lee, Stuart; Seluzicki, Adam; Golden, Susan S (2019). “Daylight Saving Time Effects”. Center for Circadian Biology.

Berk, Michael; Dodd, Seetal; Hallam, Karen; Berk, Lesley; Gleeson, John; Henry, Margaret (2008). “Small Shifts in Diurnal Rhythms Are Associated with an Increase in Suicide: The Effect of Daylight Saving”. Sleep and Biological Rhythms.

Block, Gene; Meijer, Johanna (2019). “Who Wants to Go to Work in the Dark? Californians Need Permanent Standard Time”. UCLA Newsroom.

Brueck, Hilary (2019). “Daylight-Saving Time Is Literally Killing Us”. Business Insider.

Clay, Joanna (2019). “Is Year-Round Daylight Saving Time a Good Idea? Maybe Not”. USC News.

Herf, Michael (2019). “Why Standard Time Is Better”. Medium.com.

Herf, Michael; Longcore, Travis (2018). “Why Proposition 7 Is Bad for Public Health”. Medium.com.

Ingraham, Christopher (2019). “How Living on the Wrong Side of a Time Zone Can Be Hazardous to Your Health”. The Washington Post.

Jin, Lawrence; Ziebarth, Nicolas R (2019). “Sleep, Health, and Human Capital: Evidence from Daylight Saving Time”. The National Bureau of Economic Research.

Livingston, Amy (2016). “Is Daylight Savings Time Helpful or Harmful? — History & Effects”. Money Crashers.

Medina, Diana; Ebben, Matthew; Milrad, Sara; Atkinson, Brianna; Krieger, Ana C (2015). “Adverse Effects of Daylight Saving Time on Adolescents’ Sleep and Vigilance”. Journal of Clinical Sleep Medicine.

Meijer, Johanna; Foster, Russell (2018). “Time to Change — But Only to ‘Wintertime’”. Daylight Academy.

O’Callaghan, Lauren (2016). “Early Riser? Waking Up Before Sunrise Increases Risk of a Stroke”. Express.

Peralta, Jessica (2019). “Why Daylight Saving Time Makes You Feel Terrible”. Healthline.

Roenneberg, Till; Winnebeck, Eva C; Klerman, Elizabeth B (2019). “Daylight Saving Time and Artificial Time Zones — A Battle Between Biological and Social Times”. Frontiers in Physiology.

Roenneberg, Till; Wirz-Justice, Anna; Skene, Debra J; Ancoli-Israel, Sonia; Wright, Kenneth P; Dijk PhD FRSB FMedSci, Derk-Jan; Zee, Phyllis; Gorman, Michael R; Winnebeck, Eva C; Klerman, Elizabeth B (2019). “Why Should We Abolish Daylight Saving Time?”. Journal of Biological Rhythms.

Watson MD MSc, Nathaniel F (2019). “Time to Show Leadership on the Daylight Saving Time Debate”. Journal of Clinical Sleep Medicine.

Zick, Cathleen D (2013). “Does Daylight Savings Time Encourage Physical Activity?”. Journal of Physical Activity and Health.

“Impact of Daylight Savings on Productivity” (ND). COFCO.

“Joint Statement to the EU Commission on DST” (2019). European Sleep Research Society.

“SRBR Talking Points About Daylight Saving Time” (2019). Society for Research on Biological Rhythms.

“To the EU Commission on DST” (2018). European Biological Rhythms Society.

References: Public Safety

Achenbach, Joel (2019). “Springing Forward to Daylight Saving Time Is Obsolete, Confusing and Unhealthy, Critics Say”. Chicago Tribune.

Boynton, Donna (2015). “Deadly Car Crashes Spike After Changing Clocks for Daylight Saving Time”. Telegram.com.

Merline, John (2018). “Time to Ditch Daylight Saving Time — It’s a Killer That Doesn’t Save Energy”. Investor’s Business Daily.

Smith, Austin C (2016). “Spring Forward at Your Own Risk: Daylight Saving Time and Fatal Vehicle Crashes”. American Economic Journal.

“For Kids’ Sake, Vote No on Year-Round Daylight-Saving Time” (2018). The Mercury News.

References: Energy & Environment

Albeck-Ripka, Livia (2018). “Daylight Saving Time Isn’t Saving Much Energy”. The New York Times.

Bambrick, Gail (2014). “Daylight Saving Time Does Not Save Energy”. Phys.org.

Block, Melissa (2007). “The Reasoning Behind Changing Daylight-Saving”. NPR.

Cohen, Benyamin (2019). “Do We Still Need Daylight Saving Time?”. Mother Nature Network.

Handwerk, Brian (2013). “Daylight Saving Time 2013: When Does It End? And Why?”. National Geographic.

Kotchen, Matthew J; Grant, Laura E (2008). “Does Daylight Saving Time Save Electricity?”. Centre for Economic Policy Research.

Kotchen, Matthew J; Grant, Laura E (2008). “Does Daylight Saving Time Save Energy? Evidence from a Natural Experiment in Indiana”. The National Bureau of Economic Research.

Porter, Catherine (2008). “Why Daylight Saving Time Is Bad for the Environment”. The Star.

References: Economy

Barnes, Christopher M; Wagner David T (2009). “Changing to Daylight Saving Time Cuts into Sleep and Increases Workplace Injuries”. Journal of Applied Psychology.

Gibson, Matthew; Shrader, Jeffrey (2015). “Time Use and Productivity: The Wage Returns to Sleep”. Williams College Department of Economics Working Papers.

Giuntella, Osea; Mazzonna, Fabrizio (2017). “Sunset Time and the Economic Effects of Social Jetlag Evidence from US Time Zone Borders”. Journal of Health Economics.

Wagner, David T (2014). “The Economic Toll of Daylight Saving Time”. The New York Times.

Wagner, David T; Barnes, Christopher M; Lim, Vivien KG; Ferris, D Lance (2012). “Lost Sleep and Cyberloafing: Evidence from the Laboratory and a Daylight Saving Time Quasi-Experiment”. Journal of Applied Psychology.

References: Religious Freedom

Eller, Sandy (2018). “Florida’s Proposed Change to Permanent Daylight Savings Time Could Create Halachic Problems for Jewish Community”. Vos Iz Neias?.

“Orthodox Group Asks Congressman to Withdraw Year-Round Daylight Time Bill” (1972). Jewish Telegraph Agency.

References: Late Sunrises

“Sunrise, Sunset, and Daylength” (ND). Time and Date AS.

References: Public Opinion

Ballard, Jamie (2019). “54% of Americans Would Support Ending Daylight Saving Time”. YouGov.

Schreuer, Milan (2018). “EU Will Let Countries Decide Whether to Use Daylight Saving”. The New York Times.

Sistek, Scott (2019). “Killing Time (Changes): Better to Permanently Keep Daylight Saving Time? Or Standard Time?”. KOMO News.

“2018 Official Endorsements November 6, 2018 Elections” (2018). California Democratic Party.

“Just 33% See the Purpose of Daylight Saving Time” (2014). Rasmussen Reports.

“Official Ballot — Consolidated General Election — City and County of San Francisco — November 6, 2018” (2018). San Francisco Department of Elections.

“Residents Face Setbacks When It’s Time to Spring Forward” (2018). PEMCO Insurance.

“Summertime Consultation: 84% Want Europe to Stop Changing the Clock” (2018). European Commission.

References: Learn from History

Clark, James C (2018). “Daylight Saving Year-Round: Once a Disaster, Always a Disaster”. Orlando Sentinel.

Downing, Michael (2005). “Endless Summer”. The New York Times.

Downing, Michael (2018). “One Hundred Years Later, the Madness of Daylight Saving Time Endures”. Smithsonian.

Jenkins, Evan (1974). “Schools Ask End to Daylight Time”. The New York Times.

Ripley, Anthony (1974). “Senate Votes Return to Standard Time for Four Months and Sends Bill to Ford”. The New York Times.

Steade, Susan (2016). “The Year Daylight Saving Time Went Too Far”. The Mercury News.

“British Summer Time: Why Do We Change the Clocks?” (2018). Yorkshire Evening Post.

“Russia: Putin Abolishes ‘Daylight Savings’ Time Change” (2014). BBC News.

References: Objective Reality

Bryner, Jeanna (2019). “Daylight Saving Time 2019: A Guide to the When, Why, What, and How”. Live Science.

Skeldon, Anne C; Dijk PhD FRSB FMedSci, Derk-Jan (2019). “School Start Times and Daylight Saving Time Confuse California Lawmakers”. Current Biology.

Stoneham, Bray (2017). “Starting Work Before 10am Is Comparable to ‘Torture’, Study Reveals”. Australian Men’s Health.

“The Equation of Time” (2017). The United States Naval Observatory.

References: Simplest Solution

Craven, Scott (2019). “Daylight Saving Time Begins Sunday: Who Observes It, Will It Affect Health?”. Iowa City Press-Citizen.

Skelton, George (2018). “Year-Round Daylight Saving Time? More Dark Mornings Is Just One Downside”. Los Angeles Times.

Written by

Permanent #StandardTime is best for health, safety, kids, and workers. And it’s the quickest end to Daylight Saving Time (DST) clock change. Jay Pea, Founder

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