Sunshine Protection Act
The Sunshine Protection Act refers to a series of bills introduced in the U.S. Congress since 2018 to establish permanent daylight saving time (DST) nationwide, thereby eliminating the biannual transitions between standard time and DST mandated by the Uniform Time Act of 1966.[1] Under the proposed legislation, DST would become the year-round standard, with exemptions allowed only for states or territories already opting out of DST, such as Hawaii and most of Arizona.[2] The act's primary stated aims include reducing disruptions from clock changes and extending evening daylight for economic and recreational benefits, though empirical analyses have questioned the net advantages.[3] Introduced initially as S.3471 in the 115th Congress, the bill gained traction amid public frustration with time shifts, passing the Senate unanimously via voice vote in March 2022 as S.623 in the 117th Congress, but it stalled in the House and was not enacted.[2] Subsequent reintroductions, including H.R.1279 in the 118th Congress and both S.29 and H.R.139 in the 119th Congress starting January 2025, have similarly advanced little beyond committee referral, reflecting partisan divides and competing proposals for permanent standard time instead.[1] As of October 2025, no version has become law, leaving the U.S. to observe DST from the second Sunday in March to the first Sunday in November annually.[4] The proposal has sparked debate grounded in circadian biology and health data, with proponents citing potential reductions in seasonal adjustment disruptions—such as the observed spikes in myocardial infarctions, strokes, and traffic fatalities following the spring DST onset.[5][6] However, opposition from organizations like the American Academy of Sleep Medicine emphasizes that permanent DST would exacerbate chronic misalignment between clock time and solar noon, leading to darker winter mornings that increase risks for schoolchildren commuting and evening chronotypes, while empirical evidence favors permanent standard time for aligning with human physiology and minimizing overall morbidity.[7][8] Studies indicate no reliable energy savings from DST and possible increases in electricity use, undermining historical justifications for the policy.[9]Historical Context
Origins of Daylight Saving Time in the United States
Daylight saving time (DST) in the United States originated as a wartime measure during World War I to conserve energy resources. Although satirical suggestions for shifting clocks appeared as early as Benjamin Franklin's 1784 essay proposing Parisians rise earlier to utilize morning daylight, serious advocacy began in the early 20th century. In 1907, British builder William Willett proposed advancing clocks seasonally to extend evening daylight for recreation, influencing later ideas, but U.S. adoption was driven by exigencies of war rather than leisure.[10][11] Germany implemented DST on April 30, 1916, to reduce artificial lighting needs and save coal for the war effort, prompting Allied nations to consider similar steps. In the U.S., amid fuel shortages and mobilization for World War I, Senator William P. Calder of New York introduced legislation to establish standard time zones and DST. The resulting Standard Time Act, also known as the Calder Act, was signed into law by President Woodrow Wilson on March 19, 1918, formalizing five time zones and mandating a one-hour clock advancement during summer months.[10][12][13] DST took effect nationwide on March 31, 1918, at 2:00 a.m., with clocks turned forward one hour until October 27, 1918, extending the period to seven months in its inaugural year. The policy aimed to align daylight with peak activity hours, purportedly saving fuel equivalent to illuminating major cities, though contemporary debates highlighted opposition from agricultural interests concerned about disrupted routines and livestock schedules. Compliance was enforced federally, marking the first uniform national observance, but public and sectoral resistance led to its repeal by joint resolution on August 20, 1919, shortly after the war's end.[14][12][10]Evolution and Empirical Critiques of DST Practices
Daylight saving time (DST) in the United States originated as a wartime measure under the Standard Time Act of March 19, 1918, which established DST from the last Sunday in March to the last Sunday in October to conserve energy during World War I.[10] The policy was repealed in 1919 amid opposition from agricultural and business interests, resulting in fragmented local implementations and over 400 variations in time observance by the early 1960s.[11] During World War II, the federal government mandated year-round DST from February 9, 1942, to September 30, 1945, under the War Time Act to support war production efficiency.[10] Postwar inconsistencies prompted the Uniform Time Act of 1966, which standardized DST nationwide from the last Sunday in April to the last Sunday in October, while allowing states to opt out entirely if uniform across the state.[11] The 1973–1974 Arab oil embargo led to a year-round DST experiment from January 6, 1974, to October 27, 1975, under the Emergency Daylight Saving Time Energy Conservation Act, but public backlash over darker winter mornings—linked to increased risks for schoolchildren—ended the trial early.[15] Subsequent extensions occurred, including a 1986 law shifting DST to the first Sunday in April, and the Energy Policy Act of 2005, effective 2007, expanding it to the second Sunday in March through the first Sunday in November to purportedly enhance energy savings and align with school and work schedules.[10] Empirical analyses of DST's energy conservation rationale, originally tied to reduced evening lighting needs, have consistently found negligible or null overall effects. A review of multiple U.S. studies concluded that none demonstrated statistically significant energy savings different from zero, with some simulations indicating slight increases due to heightened air conditioning use outweighing lighting reductions.[16] Clock transitions disrupt circadian rhythms, with the spring shift to DST associated with acute health risks, including a 24% increase in myocardial infarction incidence in the following week and elevated stroke rates, as evidenced by population-level data from multiple countries.[6] Chronic misalignment under DST exacerbates sleep deprivation, worsening mental health outcomes like depression and anxiety, particularly in adolescents whose biological clocks delay naturally.[17] Safety critiques reveal mixed but predominantly negative transition effects. The spring DST onset correlates with approximately 30 additional annual U.S. fatal vehicle crashes from 2002–2011, attributable to sleep loss impairing reaction times and awareness, imposing a social cost exceeding $275 million yearly.[18] While permanent DST might reduce evening rush-hour accidents via extended daylight, transition-induced spikes in crashes and poorer driving metrics—such as increased risk-taking—persist, with the American Academy of Sleep Medicine advocating permanent standard time to minimize these harms.[7] On crime, DST's evening light extension has been linked to reductions in robberies and violent offenses, with one analysis estimating significant social benefits from decreased criminal activity outweighing costs in some models.[19] Productivity and economic impacts further question DST's net value. Sleep disruption from transitions leads to measurable declines in workplace performance and cognitive function, contributing to higher healthcare costs and lost output estimated in billions annually.[20] Although proponents cite leisure and retail benefits from later sunlight, rigorous assessments indicate these do not offset health and safety detriments, with professional sleep organizations concluding that standard time better aligns human physiology with solar cycles for optimal societal functioning.[7]Legislative Origins
Initial Federal Proposals
The Sunshine Protection Act was first introduced at the federal level as S. 2537 in the 115th United States Congress on March 12, 2018, by Senator Marco Rubio (R-FL).[21] The bill sought to amend Section 3 of the Uniform Time Act of 1966 (15 U.S.C. 260a) by eliminating the requirement for biannual clock changes and designating daylight saving time as the permanent standard time throughout the United States, with provisions allowing states to opt out via legislation approved by Congress. This proposal was directly modeled on Florida's state-level H.B. 1013, enacted on March 23, 2018, which similarly petitioned for federal authorization to adopt permanent daylight saving time year-round.[21] The legislation was referred to the Senate Committee on Commerce, Science, and Transportation but received no further action, lapsing at the end of the 115th Congress in January 2019. Proponents, including Rubio, argued that permanent daylight saving time would promote energy conservation, reduce traffic accidents, and support economic activities like tourism and retail by extending evening daylight, drawing on historical precedents such as the temporary year-round daylight saving time implemented under the Emergency Daylight Saving Time Energy Conservation Act of 1973.[22] However, the bill faced implicit hurdles from federal law's longstanding deference to standard time as the baseline, requiring congressional override of state exemptions under the Uniform Time Act.[23] No companion bill was introduced in the House during this initial session, marking the proposal's origin as a Senate-led initiative tied to Florida's advocacy for extended daylight to benefit its subtropical climate and outdoor economy.[21]Florida's Role and Early State Support
In March 2018, the Florida House of Representatives passed House Bill 1013 by a vote of 103-10, expressing the state's legislative intent to adopt daylight saving time (DST) year-round if authorized by federal law, thereby becoming the first U.S. state to formally pursue permanent DST. The bill, signed into law by Governor Rick Scott on March 23, 2018, and codified in Florida Statutes as the state-level Sunshine Protection Act (Section 1.025), cited potential economic advantages from extended evening daylight, particularly for tourism, outdoor recreation, and retail sectors in Florida's subtropical climate where sunrise times are already relatively late during standard time periods.[24][25] Florida's action aligned with longstanding local preferences for maximizing afternoon sunlight, driven by empirical observations of increased activity and commerce during DST months, and it directly influenced federal advocacy led by Florida's congressional delegation, including Senator Marco Rubio's introduction of S. 2537, a national Sunshine Protection Act, on March 12, 2018.[21] The state's push underscored causal benefits of permanent DST in southern latitudes, where clock changes disrupt fewer morning routines compared to northern states, prioritizing evening productivity over early sunrises that often coincide with lower population activity levels.[26] Florida's initiative spurred early adoption in other states seeking similar exemptions; by 2019, Delaware, Maine, Oregon, Tennessee, and Washington had enacted comparable legislation contingent on congressional approval, reflecting a growing regional consensus in favor of DST permanence amid critiques of biannual transitions' health and efficiency costs.[27] These measures collectively highlighted state-level momentum, with Florida's pioneering effort providing a model for overriding the Uniform Time Act of 1966's DST mandate through targeted federal amendments.[28]Key Provisions
Establishment of Permanent Daylight Saving Time
The Sunshine Protection Act amends section 3(a) of the Uniform Time Act of 1966 (15 U.S.C. § 260a(a)) to eliminate the seasonal observance of daylight saving time, replacing the temporary advancement of clocks—from the second Sunday in March to the first Sunday in November—with a permanent designation of the advanced time as the standard time zone throughout the United States.[29][1] This change would abolish the biannual clock adjustments, preventing the spring-forward and fall-back transitions that have been federally mandated since 1966, except during periods of wartime suspension or state exemptions.[30] Implementation would occur without an explicit delayed effective date in the bill text, though prior iterations specified advancement at 2:00 a.m. on the first Sunday in November following enactment to align with the existing fall transition.[30] The provision preserves exemptions for states or territories currently observing standard time year-round, such as Hawaii and most of Arizona, allowing them to maintain their status unless they elect otherwise; no new opt-out mechanism is created for states currently complying with DST.[29] This federal override would supersede any conflicting state laws enforcing clock changes, standardizing advanced time as the default unless Congress grants further exemptions.[31] Proponents argue this permanence reduces disruptions from time shifts, citing energy savings claims from extended evening daylight, though empirical data on net economic benefits remains debated; the bill itself contains no provisions for studies or pilots to verify such outcomes post-enactment.[32] The act's core mechanism relies on redefining "standard time" under federal law, shifting the baseline without altering the underlying solar time calculations or time zone boundaries.[1]Provisions for State and Territorial Exemptions
The Sunshine Protection Act preserves exemptions for states and areas within states that are currently authorized to abstain from daylight saving time observance, allowing them to elect permanent standard time instead of adopting the nationwide permanent daylight saving time. Under the bill, such exemptions apply to jurisdictions like the state of Hawaii and the majority of Arizona (excluding the Navajo Nation, which observes DST), which have long operated on permanent standard time by virtue of state laws approved under the Uniform Time Act of 1966.[1][29] U.S. territories that do not observe daylight saving time, including Puerto Rico, Guam, American Samoa, the U.S. Virgin Islands, and the Northern Mariana Islands, would similarly be exempt from the mandate for permanent daylight saving time and could continue using permanent standard time.[4] These provisions ensure that the bill's redefinition of daylight saving time as the new permanent standard—effective upon enactment—does not override pre-existing opt-outs, thereby respecting local legislative choices without requiring federal intervention for single-time-zone territories.[1] Election of an exemption would necessitate affirmative legislative action by the state or territorial government, consistent with federal requirements under 15 U.S.C. § 260 et seq., which generally prohibit deviations unless confined to one time zone or approved by Congress. No additional federal opt-out mechanism is created for non-exempt states, limiting broader exemptions to those already in place.[29][27]Legislative History
2018-2021 Introductions and Stagnation
In March 2018, Senator Marco Rubio introduced S. 2537, the Sunshine Protection Act of 2018, in the 115th Congress, aiming to amend the Uniform Time Act of 1966 by establishing permanent daylight saving time nationwide, effective immediately upon enactment, while preserving exemptions for states like Hawaii and most of Arizona.[21] The bill was referred to the Senate Committee on Commerce, Science, and Transportation but received no further action, including no committee hearings or votes, amid broader congressional priorities and ongoing debates over the empirical merits of clock changes. President Donald Trump publicly expressed support via Twitter, stating he would sign such legislation to end the biannual adjustments, yet the bill stalled without advancing. This introduction followed Florida's state-level push, where Governor Rick Scott signed SB 858 in 2018 urging federal authorization for permanent daylight saving time to extend evening sunlight for tourism and economic activity.[33] The legislation saw reintroduction in the 116th Congress on March 6, 2019, as S. 670 in the Senate, cosponsored by Rubio and Senator Rick Scott, alongside companion H.R. 1556 in the House by Representative Vern Buchanan, both seeking to repeal the seasonal transition to standard time and lock in daylight saving time permanently.[34] [35] Proponents argued it would reduce disruptions from clock shifts, citing data on increased traffic accidents post-adjustment, though no committee markup or floor consideration occurred, reflecting stagnation linked to divided stakeholder interests, including agricultural and education sectors favoring standard time alignment with solar noon. No equivalent bill advanced in 2020 during the 116th Congress's final session, hampered by the COVID-19 pandemic's disruption of legislative agendas and focus on emergency measures.[27] By early 2021, in the 117th Congress, S. 623 was introduced as the Sunshine Protection Act of 2021, again led by Rubio with bipartisan cosponsors including Senator Ed Markey, proposing implementation by November 2023 to allow transitional planning.[2] Despite accumulating support from over 30 states via resolutions urging federal action—such as Tennessee's 2018 law and subsequent adoptions—the bill remained in the Senate Committee on Commerce, Science, and Transportation through 2021, with no hearings or votes, underscoring persistent inertia from unresolved tensions between permanent daylight saving time's purported retail and safety gains versus evidence of health costs like circadian misalignment.[27] This period's repeated introductions without progression highlighted congressional reluctance to prioritize time policy amid competing fiscal and social issues, despite public polls showing majority opposition to biannual changes.[23]2022 Senate Passage and House Failure
On March 15, 2022, the United States Senate passed S. 623, the Sunshine Protection Act of 2021, by unanimous consent without recorded debate or amendments beyond a technical adjustment to establish permanent daylight saving time (DST). Sponsored by Senator Marco Rubio (R-FL) with cosponsors including Senator Patty Murray (D-WA), the bipartisan legislation aimed to eliminate biannual clock changes by designating DST as the standard time nationwide, effective November 5, 2023, while preserving exemptions for states like Hawaii and Arizona.[30] The measure received voice vote approval, reflecting broad initial support amid public frustration with clock adjustments, though it bypassed committee review, which later drew criticism from some members for lacking scrutiny.[36] The bill's swift Senate advancement contrasted with prior stagnation, building on reintroductions since 2018 and fueled by arguments for economic benefits and reduced disruption, despite empirical evidence from past experiments—like the 1974 Emergency Daylight Saving Time Energy Conservation Act, repealed after public backlash over safety concerns—indicating potential drawbacks such as darker winter mornings increasing risks for commuters and schoolchildren.[37] Proponents cited polls showing majority public preference for permanent DST, but the legislation's passage highlighted procedural ease rather than rigorous evaluation of causal health and safety data, including studies linking clock shifts to increased heart attacks and accidents.[38] Following Senate approval, the bill was received in the House of Representatives on March 16, 2022, and referred to the Committee on Energy and Commerce, where it stalled without hearings or votes. House inaction stemmed from competing legislative priorities, including budget reconciliation and responses to Russia's invasion of Ukraine, alongside divisions over whether permanent DST or standard time better aligned with circadian biology and traffic safety data favoring the latter.[39] Critics in both chambers, informed by historical repeals and recent analyses questioning DST's energy savings claims, argued for permanent standard time to mitigate empirically documented disruptions like sleep deprivation and crime spikes post-time change, preventing the bill from advancing before the 117th Congress adjourned.[40]Reintroductions in 2023-2025
In the 118th United States Congress, the Sunshine Protection Act was reintroduced in the Senate as S. 582 on March 1, 2023, sponsored by Senator Marco Rubio (R-FL) with bipartisan cosponsors including Senator Ed Markey (D-MA).[41] [42] A companion bill, H.R. 1279, was introduced simultaneously in the House by Representative Vern Buchanan (R-FL).[31] [43] Both measures proposed establishing permanent daylight saving time nationwide, subject to exemptions for certain states and territories, but were referred to committees—Senate Commerce, Science, and Transportation for S. 582 and House Energy and Commerce for H.R. 1279—without advancing to floor votes or hearings during the session spanning 2023 and 2024.[44] The lack of progress in the 118th Congress reflected ongoing divisions over permanent daylight saving time versus permanent standard time, despite prior Senate passage in 2022, with no recorded motions or debates on the reintroduced bills.[4] Entering the 119th Congress in 2025, the legislation was reintroduced in the House as H.R. 139 on January 3 by Representative Buchanan and in the Senate as S. 29 on January 7 by Senator Rick Scott (R-FL), supported by cosponsors including Senator Patty Murray (D-WA).[29] [1] [45] [46] These versions retained the core provisions for year-round daylight saving time, with H.R. 139 garnering over 25 cosponsors and S. 29 attracting 18 by mid-2025.[47] [48] Referred to the same committees as prior iterations, the bills underwent no substantive action, including hearings, amid continued state-level advocacy but federal inertia as of October 2025.[49] [4]Scientific and Health Evidence
Circadian Rhythm Disruptions from Clock Changes
The human circadian rhythm, an approximately 24-hour internal cycle regulated by the suprachiasmatic nucleus in the hypothalamus and primarily entrained by environmental light cues, becomes misaligned during daylight saving time (DST) transitions due to the abrupt shift in civil time relative to solar time. In the spring forward transition, clocks are advanced by one hour, effectively shortening sleep duration by that amount on the first night and delaying the sunrise by an hour relative to social schedules, which delays the morning light signal that normally advances the circadian phase. This results in a temporary desynchronization, or "social jet lag," where biological rhythms lag behind clock time, impairing sleep onset, duration, and quality.[5][50] Empirical studies demonstrate that this misalignment disrupts physiological processes beyond sleep, including melatonin suppression and cortisol elevation at mismatched times, exacerbating fatigue and cognitive impairment in the days following the change. Actigraphy and polysomnography data from controlled observations show reduced total sleep time and increased sleep fragmentation post-transition, with recovery typically requiring several days to a week as the body gradually phase-advances. The fall back transition, while allowing an extra hour of sleep initially, advances evening light exposure relative to the internal clock, potentially delaying circadian phase and contributing to later bedtimes and chronic misalignment over winter months.[51][52] Health consequences linked to these disruptions include acute elevations in cardiovascular strain, with multiple analyses reporting a modest but statistically significant increase in acute myocardial infarction incidence—up to 24-27% on the Monday following spring forward—attributed to sleep loss and sympathetic nervous system activation disrupting vascular homeostasis. However, some large-scale registry studies, examining over 170,000 patients, find no overall spike in events around transitions, suggesting the effect may be confined to vulnerable subgroups or confounded by behavioral factors like altered meal timing. Circadian misalignment from repeated biannual shifts has also been associated with broader risks, including heightened stroke incidence and metabolic dysregulation, underscoring the causal role of phase desynchrony in amplifying morbidity.[53][54][55]Comparative Impacts of Permanent DST vs. Permanent Standard Time
Permanent standard time aligns more closely with human circadian rhythms by synchronizing clock time with solar noon, facilitating morning light exposure that entrains the body's internal clock and promotes alertness during peak activity hours.[5] In contrast, permanent daylight saving time shifts clocks forward year-round, resulting in later winter sunrises—up to two hours after clock time in northern latitudes—which delays circadian phase and reduces morning photic input essential for suppressing melatonin and enhancing wakefulness.[7] The American Academy of Sleep Medicine endorses permanent standard time as optimal for circadian health, citing evidence that daylight saving time induces chronic misalignment akin to jet lag, exacerbating sleep debt and diurnal variation in performance.[5][7] Empirical modeling of nationwide health outcomes indicates permanent standard time yields greater benefits than permanent daylight saving time. A 2025 Stanford University analysis, using circadian-informed simulations across U.S. zip codes, projected that permanent standard time would reduce obesity prevalence by 0.78 percentage points, cardiovascular disease by 0.06 percentage points, and type 2 diabetes by 0.13 percentage points, compared to smaller reductions under permanent daylight saving time (0.23, 0.02, and 0.04 points, respectively).[56] These disparities stem from permanent standard time's preservation of earlier sunrises, which bolster morning cortisol peaks and metabolic regulation, whereas permanent daylight saving time's evening light bias correlates with delayed sleep onset and prolonged exposure to artificial light, heightening risks for metabolic disorders.[56][57] Peer-reviewed consensus from sleep medicine bodies reinforces that permanent standard time mitigates vulnerabilities in adolescents, shift workers, and the elderly, who suffer amplified misalignment under permanent daylight saving time due to inherent phase delays or reduced adaptability.[7]| Health Metric | Projected Reduction with Permanent Standard Time | Projected Reduction with Permanent DST |
|---|---|---|
| Obesity Prevalence | 0.78 percentage points | 0.23 percentage points |
| Cardiovascular Disease | 0.06 percentage points | 0.02 percentage points |
| Type 2 Diabetes | 0.13 percentage points | 0.04 percentage points |