This week the House voted to make Daylight Savings Time permanent, by a vote of 308-117 and with the support of President Trump, who has been advocating for the bill for months. The President had specifically recommended including the bill as a provision within the BUILD America 250 Act, which is still awaiting floor consideration. Having now passed the House, the “Sunshine Protection Act” could move independently in the Senate, although passage by unanimous consent in the Senate does not appear possible and therefore the bill would require floor time.

Clock Preference

Despite the wide margin of support in the House, the politics of permanent DST are somewhat complicated, and while there is bipartisan support for permanent DST there is also bipartisan opposition. According to a poll of American adults although few people like changing the clocks (12 percent of respondents), opinions are split on whether to keep the clocks at Daylight Savings Time (56% support) versus Standard Time (42%)

Preference between DST and Standard time is affected somewhat by an individual’s schedule and priority for morning versus evening sunshine, but there is also a geographic component to the preference. Generally, standard time orients time so that the sun is at the zenith of the sky (“solar noon”) at clock noon on average for the time zone, as noon is assumed to be the middle point of one’s waking hours. DST shifts clock noon later by an hour. Within a single time zone though, those at the eastern border of the zone will experience a solar noon earlier than 12pm under standard time and those on the western border will conversely see the solar noon later in the day. Daylight Savings Time shifts that late clock for those on the western edges even further back. So as a result, while communities on the eastern edge of their time zone may enjoy permanent DST, those on the western edge could see a significant separation between sunlight hours and school/work schedules.

As an example, Russell Spring, KY sits on the eastern edge of the Central time zone, so today their solar noon was 12:46pm with sunrise at 5:32am and sunset at 7:59pm. Six months ago (under standard time), their solar noon was 11:50, and sunrise and sunset were 6:52am and 4:49pm respectively. Had DST been permanent in January, those times would instead have been 7:52 and 5:49, which might be preferable given work schedule norms. Conversely if Standard Time were permanent, the sun would have risen in Russell Springs today at 4:32am, which is a lot of daylight wasted for most people’s schedules.

In contrast, Indianapolis, IN sits near the western edge of the Eastern time zone. Under Daylight Savings Time, today their solar noon occurred at 1:50pm, and the sun rose at 6:29 and will set at 9:11pm. Six months ago, under Standard Time their solar noon occurred at 12:54, with sunrise at 8:03am and sunset at 5:46pm. Had DST been permanent, sunrise would have been at 9:03am, which many might say prolongs the morning dark too long into normal school hours. Locations further north, with shorter winter sunlight hours, would see even more significant encroachment of dark into normal school and work hours. For instance in northwest North Dakota, sunrise in winter months is already near 9am under standard time; permanent DST would make that 10am. (If curious, check your own location’s solar noon here.)

Implications and Political Response

A growing body of scientific research has demonstrated that the “jetlag” resulting from changing the clock time on a biannual basis has negative impacts on public health, including the sleep impacts, greater rates of traffic crashes and workplace safety impacts. On the other hand, research also points to negative health impacts of later sunsets, including greater rates of obesity, heart disease, diabetes and cancer, which might point policymakers toward making Standard Time permanent rather than DST, which makes sunset an hour later.

In response to House passage of the Sunlight Protection Act, Airlines for America raised concerns about “considerable implications for aviation, including passenger disruption, crew and aircraft positioning, and domestic and international connectivity issues.”

Response in the Senate has been mixed, despite the Senate having (accidentally?) passed the same bill by unanimous consent in 2022. The current Senate companion is led by Sens. Rick Scott (R-FL) and Patty Murray (D-WA) and has 17 additional cosponsors. However in a statement to reporters this week Sen Barrasso said that the bill would not pass by unanimous consent this time around, calling the politics “not as simple” as bill sponsors might like.

Senator Cotton (R-AR) made his feelings clear in a floor speech last year, saying “I didn’t personally object in 2022 for two reasons. First, I hadn’t adequately communicated to my staff the depth of my opposition to this bill. Second, because of a miscommunication, I expected another senator who also opposed the bill to object. I take full responsibility for this mistake, though the search for someone else to blame is actively ongoing.”

History of Time Zones and DST

The history of time zones in the U.S. falls into several eras. In the first era, prior to 1883, each city largely followed “sun time” and set its own time, with the result that there were more than 144 different local times in the U.S. When traveling and communication became fast enough that people and messages could cross multiple time zones (e.g. once travel by rail and communication by telegraph became prevalent), this started to create confusion and pose scheduling challenges, so starting in the 1870s, the major railroads started working together to identify a solution and in 1883 at a conference in Chicago they official adopted created their own set of four time zones to coordinate schedules. (This association, originally known as “The Time-Table Convention” is the organization now known as The Association of American Railroads.)

The second era began during WWI, when Daylight Savings Time was established through the Calder Act, (aka the Standard Time Act of 1918), which also established the five standard time zones for the country, and authorized the Interstate Commerce Commission (ICC) to adjust those boundaries as necessary. DST was a wartime measure that was then abolished at the federal level following the war although some states continued to observe it.

In WWII, Congress implemented year-round DST, e.g. “War Time” to try to reduce evening electricity use by households in order to preserve energy capacity for defense production. War Time ended following the conclusion of the war.

Then in 1961, the ICC shared their view with Congress that the authority for states and localities to determine whether or not to follow standard time was creating challenges for interstate commerce. In response, Congress passed the Uniform Time Act of 1966, which mandated standard time for the winter, and created standard dates for the start and end of DST, while allowing States to opt out of DST.

The most recent change to time occurred during the 1973 oil embargo, when Congress passed the Emergency Daylight Saving Time Energy Conservation Act to create a permanent DST one-year trial period. Even before the trial period ended, Congress amended the law to observe a shorter 4 month standard time within the one year trial, and following the trial period the country reverted to current practice of changing clocks.

International Practice

Variations across countries’ practice of DST is one challenge cited as a benefit of permanent DST, as time-zone coordination for companies and individuals scheduling meetings across multiple time zones is complicated by the practice of changing clock times.

America is not the only country that practices daylight savings time clock changes. Though few countries in Asia change their clocks, most European nations practice DST as does most of Canada, which treats it as a matter of provincial or territorial concern. Nor is America the only country to be considering scrapping the practice In 2019, the European Parliament passed a proposal to develop a final law to eliminate DST and allow each member state to decide whether to change clocks or stay permanently on summer time or winter time, however logistical concerns have prevented the proposal from moving forward.