Ciekawostka: Daylight Saving Time is not observed in most of the state of Arizona and parts of Indiana

Evidence: 64 • authority: 72

Most of the United States observes daylight saving time (DST), the practice of setting the clock forward by one hour when there is longer daylight during the day, so that evenings have more daylight and mornings have less. Exceptions include Arizona (except for the Navajo Nation, which observes daylight saving time), Hawaii, and the territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the United States Virgin Islands. The Uniform Time Act of 1966 established a uniform set of rules for states opting to observe daylight saving time. In the US, daylight saving time starts on the second Sunday in March and ends on the first Sunday in November, with the time change…

Evidence: 64 • authority: 72

Daylight saving time (DST), also known as summer time, is the practice of advancing clocks during part of the year, typically by one hour around spring and summer, so that daylight ends at a later time of the day. As of 2026, DST is observed in most of Europe, most of North America and parts of Africa and Asia around the Northern Hemisphere summer, and in parts of South America and Oceania around the Southern Hemisphere summer. It was also formerly observed in other areas.

Evidence: 54 • authority: 80

Reducing Crime Through Public Policy: Evidence from the 2006 Expansion of Daylight Saving Time in Indiana

Evidence: 54 • authority: 80

Does Daylight Saving Time Save Energy? Evidence from a Natural Experiment in Indiana

Evidence: 54 • authority: 92

Daylight saving time transitions are not associated with increased seizure incidence.. Objective Given the known association of daylight saving time (DST) transitions with increased risk of accidents, heart attack, and stroke, we aimed to determine whether seizures, which are reportedly influenced by sleep and circadian disruption, also increased in frequency following the transition into DST. Methods Using Seizure Tracker's self-reported data from 12 401 individuals from 2008-2016, 932 717 seizures were assessed for changes in incidence in relation to DST transitions. Two methods of standardization-z scores and unit-scaled rate ratios (RRs)-were used to compare seizure propensities followi…

Evidence: 45 • authority: 88

How is Daylight Saving Time still a thing?: Disruptions from Daylight Saving Time transitions lead to cognitive performance deficits. Visual search, looking for targets among distractors, underlies many critical professions and must often be performed optimally regardless of the time of day, week, or year. However, external events can disrupt the ability to perform. The current study examined one such specific event: Daylight Saving Time (DST) transitions—when the clock shifts forward or backward by one hour. Performance on a visual search task was assessed using “big data” from the mobile app Airport Scanner (Kedlin Co.), wherein players serve as airport security screeners searching for pr…

Evidence: 45 • authority: 88

Daylight Saving Lives: the effect of daylight saving time on homicides. In this paper we investigate the effect of Daylight Saving Time (DST) on homicides. As assignment into the policy follows technical reports from the National Electric System Operator, the Brazilian setup lends itself to both within and between states comparison of homicide levels around the date of transition and during the whole period of DST adoption. Using a difference-in-differences strategy, we find a decrease in the number of homicides by firearms of roughly 9.83% during DST months. In line with the crime deterrence hypothesis, we show this uncovered effect is mostly concentrated in hours directly affected by the…

Evidence: 45 • authority: 80

Saving Daylight, Increasing Danger: Daylight Saving Time Leads to Less Sleep, More Injuries on the Job

Evidence: 45 • authority: 72

A time zone is an area which observes a uniform standard time for legal, commercial, and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time. Each time zone is defined by a standard offset from Coordinated Universal Time (UTC). The offsets range from UTC−12:00 to UTC+14:00, and are usually a whole number of hours, but a few zones are offset by an additional 30 or 45 minutes, such as in India and Nepal. Some areas in a time zone may use a different offset for part of the year, typically one hour ahead during spring and summ…

Evidence: 45 • authority: 72

This is a list of the UTC time offsets, showing the difference in hours and minutes from Coordinated Universal Time (UTC), from the westernmost (−12:00) to the easternmost (+14:00). It includes countries and regions that observe them during standard time or year-round. The main purpose of this page is to list the current standard time offsets of different countries, territories and regions. Information on daylight saving time or historical changes in offsets can be found in the individual offset articles (e.g. UTC+01:00) or the country-specific time articles (e.g. Time in Vatican). Places that observe daylight saving time (DST) during their respective summer periods are listed only once, at…

Evidence: 45 • authority: 72

In the United States, time is divided into nine standard time zones covering the states, territories and other US possessions, with most of the country observing daylight saving time (DST) for approximately the spring, summer, and fall months. The time zone boundaries and DST observance are regulated by the Department of Transportation, but no single official map of those existed until the agency announced intentions to make one in September 2022. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) (an agency of the Department of Commerce); and the United States Naval Observatory (USNO). Th…

Evidence: — • authority: 35