How Much Daylight Are We Really Saving? The Honest Case on DST

Twice a year, most of the country pushes the clocks an hour in one direction or the other and waits to feel different. The promise behind the ritual is that we are saving something, usually energy, sometimes daylight, sometimes both. After more than a century of trying it, the evidence has gotten clear enough to ask a fairer question. How much daylight are we really saving, and at what cost to everything else?

What Daylight Saving Time Is Supposed to Do

Daylight Saving Time (DST) shifts the clock forward one hour in the spring so the Sun appears to rise and set later by the wall clock. The reasoning is straightforward. Most of us are awake well after the morning sun is already up, so the early daylight is “wasted.” Move the clock, and that hour of light slides from a sleeping bedroom to an active evening, when more people are home, driving, shopping, and outdoors.

The promised payoff was less evening electricity for lighting and, the assumption went, less overall energy demand. That promise drove the original adoption, every extension since, and the current push for permanent DST.

The Original Energy-Savings Premise

Modern DST in the United States began as a wartime energy measure. President Woodrow Wilson signed the Standard Time Act on March 19, 1918, to reduce evening coal use during World War I. The country dropped the policy after the war and reinstated it during World War II as year-round “War Time” from February 1942 to September 1945.

The next major push came during the 1973 oil crisis. With petroleum supplies suddenly choked off, gas stations ran dry and Congress reached for any lever that might cut energy demand. DST was started much earlier than usual in both 1974 (January 6) and 1975 (February 23). The rationale was that brighter winter afternoons would save lighting energy and, as a bonus, cut traffic accidents.

The most recent extension came with the Energy Policy Act of 2005, which took effect in 2007. Since then, more than two-thirds of each year (245 days) has been in DST. Supporters of that extension claimed it would save the equivalent of 10,000 barrels of oil per day, a figure built on U.S. Department of Energy statistics from the early 1970s.

Is There a Benefit to DST?

The idea behind moving the clocks twice a year is to take better advantage of the Sun’s natural electricity, meaning its light. Most of us get out of bed after the Sun has risen and go to bed after it has set. When we spring forward and fall back, we are not really “saving” anything. We are giving up a little Sun in the morning and adding it to the evening. The honest question is whether we actually do anything useful with that borrowed evening light.

Later sunsets do encourage people to get out and do more in the evenings. Some argue that this raises gasoline consumption as we drive around more during the lighter evenings. Darker mornings also mean more electricity is needed to get ready for school and work. Whether those effects cancel the lighting savings, or swamp them, is exactly what modern studies have tried to measure.

What Modern Studies Actually Show

When the Energy Policy Act of 2005 extended DST by four weeks, Congress asked the U.S. Department of Energy to measure the result. The 2008 DOE report found that the four added weeks of DST cut total national electricity use by about 0.5%. Spread across the year and net of other variables, that is small, and it depends on the assumption that lighter evenings continue to reduce lighting demand more than darker mornings raise it.

A 2008 natural experiment in Indiana, where DST was newly adopted statewide in 2006, looked harder at residential demand and found the opposite. Researchers Matthew Kotchen and Laura Grant, working with University of California, Santa Barbara, reported that residential electricity use rose roughly 1% under DST, with the strongest effect in late summer and early fall. The likely culprit was air conditioning, which kicked in harder during the longer, warmer evenings.

California Public Utilities Commission studies through the 2000s reached similar conclusions. Net savings were small and depended heavily on climate and whether households shifted to cooling rather than lighting as the binding evening load. The modern body of research treats the energy picture as roughly nil. The original 10,000-barrels-a-day claim, extrapolated from 1970s data, has not aged well.

The Health Cost

While the energy ledger is roughly a wash, the health ledger is not. A 2014 study in the journal Open Heart found that the Monday following the spring-forward shift carries about a 24% higher rate of heart attacks than a typical Monday. A 2020 paper in Current Biology reported a 6% jump in fatal car crashes in the days after spring forward, with the effect strongest in the western parts of each time zone, where mornings are already dark. Emergency department visits rise by roughly 5% in the same window, and several studies have linked the shift to short-term spikes in stroke and mood-disorder events.

The mechanism is circadian. Body clocks run on solar cues, especially morning light. Pushing the wall clock forward forces millions of people to wake an hour earlier than their internal clocks are ready for, without the morning light needed to reset. Sleep researchers describe the result as “social jet lag” of about one hour per week, and the disruption can persist for weeks. The American Academy of Sleep Medicine has issued repeated position statements calling for an end to seasonal time changes.

The Safety Cost

The safety story has two halves, and they pull in different directions. In the spring, the risk concentrates in the first week of DST: sleep-deprived drivers on darker mornings. In the fall, after we “fall back” to Standard Time, the risk shifts to the evening commute, which suddenly happens in the dark.

The November concern is pedestrian fatalities. A 2007 Carnegie Mellon study found pedestrian deaths in the first weeks of Standard Time rose sharply at evening rush hour, with the largest effect among older walkers and children. Schools in northern states face the opposite problem in late fall and early winter, when kids walk or wait for buses in pre-dawn darkness. Neither permanent option fully solves both halves; they trade one risk window for another.

Economic Effects

The economic picture is mixed and modest. Productivity studies typically find a measurable dip on the Monday after spring forward, often called “cyberloafing Monday.” Workplace injuries on construction and mining sites rise that week as well. Airlines take a separate hit, because the U.S. and the European Union do not change clocks on the same Sunday and have to reschedule international slots twice a year. Chmura Economics & Analytics has estimated the U.S. cost of the twice-yearly time change at roughly $147 million per year in lost productivity and rescheduling. Compared with the 0.5% national energy figure, the costs are not trivial.

Remember When?

The country has run this experiment before. In response to the 1973 oil crisis, Daylight Saving Time was started much earlier than usual. In 1974 it began on January 6 and in 1975 on February 23. It sounded sensible. Bright winter afternoons, lower lighting bills, fewer late-day traffic accidents.

Nights BRIGHT, Mornings DARK

Setting the Sun an hour later also means it rises an hour later, a side effect that apparently did not “dawn” on lawmakers until the change took hold. The result was unacceptably dark mornings. In 1974, cities in the western parts of their time zones, like Detroit, Michigan, and Boise, Idaho, did not see the Sun rise until after 9:00 a.m. Mothers found themselves sending children to the school bus with flashlights. Public opinion collapsed within months. The experiment was rolled back, and in 1976 the start of DST returned to April. As the philosopher and novelist George Santayana once wrote: “Those who cannot learn from history are doomed to repeat it.” Many of the lawmakers debating a permanent shift today do not seem to remember the lesson of more than three decades ago.

Permanent DST vs Permanent Standard Time

The current debate is not really about whether to keep changing clocks twice a year. Almost no one defends the twice-a-year shuffle on its merits anymore. The debate is which permanent option to pick.

Permanent DST advocates argue for the longer evenings: more after-work daylight for recreation, retail, and youth sports. Permanent Standard Time advocates, including most sleep medicine groups, argue that morning light is the cue the human body actually needs, and that year-round DST would push winter sunrises in the northern United States to roughly 8 a.m. or later, with school commutes happening in the dark. The 1974 rollback is the empirical case study they keep pointing to.

The “Sunshine Protection Act” Debate

The current legislative push is the Sunshine Protection Act, which would make Daylight Saving Time permanent. The U.S. Senate passed it by unanimous voice vote on March 15, 2022, in a brief floor moment that surprised even some of its co-sponsors. The bill then stalled in the House of Representatives. House leadership cited the same morning-darkness concerns that ended the 1974 experiment.

The bill was reintroduced in 2023 and again in 2024, with bipartisan sponsors but no clear path to a House vote. As of 2026, no version has reached the president’s desk. The Congressional Research Service summary of federal time-zone policy remains the most up-to-date neutral reference on what would change if it ever did.

Countries That Abolished DST

The United States is not alone in the debate, and several countries have already settled it.

• Russia: Dropped the seasonal change in 2011, briefly stayed on permanent DST, then switched to permanent Standard Time in 2014 after public complaints about dark winter mornings.
• Mexico: Eliminated DST for most of the country in 2022. A few northern border municipalities still observe it for cross-border trade alignment.
• European Union: The European Parliament voted in 2019 to end the seasonal shift across the bloc. Member states have not yet agreed on whether to settle on permanent DST or permanent Standard Time, so the change has not been implemented.
• Iceland, Belarus, Turkey, and Argentina: All abolished seasonal changes years earlier and now sit on a single year-round clock.

The pattern is consistent. Once a country actually picks an option and lives with it for a year or two, public pressure to go back to clock changes does not materialize.

A Better Idea: The Farmers’ Almanac Civil-Twilight Proposal

It is not very likely that we will do away with Daylight Saving Time anytime soon, but we at the Farmers’ Almanac believe we have a better method for scheduling it. If we wish to use DST to its fullest, the primary aim should be to capture the maximum amount of daylight without causing more morning darkness.

Civil twilight is the useful measure here. Astronomers define it as: “That interval prior to sunrise or just after sunset in which enough sky illumination still exists (barring dense cloud cover) to carry on normal work out-of-doors.”

The duration of civil twilight varies during the year, but at latitude 40 degrees North, the median latitude for the contiguous United States, it generally starts about a half hour before sunrise and ends about a half hour after sunset. If we assume that most people get up to start a normal work or school day at 6:00 a.m., DST should be implemented when the start of civil twilight will coincide with that wake time. Sunrise (and full daylight) would then come a half hour later. Civil twilight at 5:00 a.m. Standard Time, or 6:00 a.m. Daylight Saving, happens during the first week of April.

For example: look at sunrise and sunset times for Philadelphia, Pennsylvania (latitude 39.9 degrees N, longitude 75.1 degrees W). To take the best advantage of civil twilight, we should “spring” ahead during the first week in April. Under the old rules, DST started between April 1 and April 7. Under the new rules, DST can now start as early as March 8 (as it did in 2015 and again in 2026). In 2007 it began on March 11. On April 7, bright morning twilight begins shortly after 6 a.m. Daylight Saving Time. Conversely, on March 8, bright morning twilight does not begin until nearly 7 a.m. Daylight Saving Time.

When Should it End?

The astronomical conditions matching early April occur again in the first week of September. Logically, that is when clocks should be set back one hour to Standard Time. In practice it makes more sense for the change to fall on the second Sunday in September, so as not to conflict with the Labor Day holiday weekend.

Even under the old rules we stayed on Daylight Saving Time far too long. By the end of October, just before clocks used to be pushed back, mornings were as dark as in early January. In New York City, sunrise on October 30 comes at 7:22 a.m. EDT, compared with 7:18 a.m. EST on January 4. Under the current rule, which extends DST for up to an additional week, the latest sunrises of the year for some locations now come about 10 to 20 minutes later than they do in early January.

The early November change from daylight back to Standard Time is abrupt. On the final Friday before we “fall back,” most commuters are going home in daylight. The following Monday they are driving in darkness. Regardless of when the time change is made, the hours of daylight will keep diminishing through the fall. Civil twilight ends earlier than 6:00 p.m. Standard Time during the second week of October. If clocks were changed in early September, people could ease into the darkness over a month, instead of in a single weekend.

What Most Sleep Scientists Recommend

If you put the energy data, the health data, and the safety data on one table, most sleep medicine groups land in the same place: year-round Standard Time. The American Academy of Sleep Medicine, the Sleep Research Society, the American Medical Association, and the National Safety Council have all issued formal positions backing permanent Standard Time over permanent DST. Their reasoning is the same: human circadian rhythms entrain to morning light, and Standard Time keeps morning light aligned with the start of the workday and the school day.

That is the opposite of what the Sunshine Protection Act would do, and the opposite of what most “give me my evenings back” advocates want to hear. There is no option without trade-offs: permanent DST trades morning safety and circadian alignment for evening daylight; permanent Standard Time trades evening daylight for morning safety and better sleep.

How to Handle the Change Well

Until Congress picks a lane, the clocks will keep moving. The good news is that you can soften the shift with three plain habits.

• Shift gradually. In the four days before the change, move your bedtime and wake time by 15 minutes a day in the direction of the new clock. By Sunday your body is roughly where the wall clock will be.
• Get morning light fast. On the Monday after spring forward, get bright outdoor light within the first 30 minutes of waking. Morning light, not coffee, is what resets the circadian clock.
• Drive carefully that week. Plan an extra few minutes for the commute. The crash data is clearest in the first week of DST and in the first week of Standard Time. Both deserve respect.

What Do You Think?

The question of just when to begin and end Daylight Saving Time, and whether to keep it at all, is genuinely contentious. At the Farmers’ Almanac we are all for ideas and methods proposed to save energy. The current scheduling of DST does not appear to fit that purpose well. There is also some ambivalence in the public mood: most people enjoy the extra evening daylight, then look forward to the end of DST in the fall, when they finally regain the hour they forfeited in the spring. We want to know what you think about the proposed permanent DST, the civil-twilight idea, or whether you would rather end the seasonal shuffle altogether. Share your opinion in the comments. The clock will move again before long either way, but the way we mark the seasons here, alongside the spring equinox in March and the winter solstice in December, ultimately matters more than any policy choice.

Frequently Asked Questions

Does Daylight Saving Time actually save energy?

Barely, and in some places not at all. The 2008 U.S. Department of Energy report measured a 0.5% national electricity reduction during the four extended weeks of DST added in 2007. A 2008 Indiana study found a roughly 1% increase in residential electricity use under DST. Net of climate, building stock, and air-conditioning load, modern research treats the energy benefit as roughly nil.

Is the spring time change really bad for your health?

The first week of DST shows measurable spikes in several outcomes. A 2014 study in Open Heart reported about a 24% increase in heart attacks on the Monday after spring forward. A 2020 Current Biology study reported a 6% rise in fatal car crashes that week. Emergency department visits rise roughly 5%. The mechanism is circadian: most adults lose around 40 minutes of sleep that night, and morning light, the body’s main clock cue, is delayed.

When does Daylight Saving Time end in 2026?

In 2026, we “fall back” to Standard Time on Sunday, November 1, 2026, at 2 a.m. local time. Clocks move back one hour, so 2 a.m. becomes 1 a.m. We “sprang forward” earlier in the year on Sunday, March 8, 2026.

Will Daylight Saving Time become permanent?

Not yet. The Sunshine Protection Act passed the U.S. Senate by unanimous voice vote on March 15, 2022, then stalled in the House of Representatives. The bill has been reintroduced in 2023 and again in subsequent sessions. As of May 2026, no version has cleared both chambers and reached the president’s desk.

Do sleep scientists prefer permanent DST or permanent Standard Time?

Permanent Standard Time. The American Academy of Sleep Medicine, the Sleep Research Society, the American Medical Association, and the National Safety Council have all issued positions backing year-round Standard Time over year-round DST. Their argument is that morning light is the cue the human body uses to reset its internal clock, and Standard Time keeps that morning light aligned with the start of the workday and the school day.

Hasn’t the United States tried permanent DST before?

Yes. In response to the 1973 oil crisis, Congress moved DST much earlier in 1974 (January 6) and 1975 (February 23). Western cities like Detroit, Michigan, and Boise, Idaho, did not see sunrise until after 9:00 a.m. on winter mornings. Mothers sent children to school bus stops with flashlights. Public opinion collapsed within months, and the start of DST was returned to April in 1976.

Which countries have abolished Daylight Saving Time?

Russia dropped seasonal changes in 2011 and settled on permanent Standard Time in 2014. Mexico eliminated DST for most of the country in 2022, keeping it only in a few northern border municipalities. The European Parliament voted in 2019 to end the seasonal shift, though member states have not yet agreed on whether to settle on permanent DST or permanent Standard Time. Iceland, Belarus, Turkey, and Argentina have also abandoned seasonal changes.

What is the Farmers’ Almanac’s own proposal?

We would tie the start and end of DST to civil twilight at latitude 40 degrees North, the median latitude for the contiguous United States. That means starting DST in the first week of April (when civil twilight at 6 a.m. Daylight Saving Time roughly matches a 6 a.m. wake time) and ending it on the second Sunday of September, easing the country into autumn darkness over a month rather than a single weekend.