|Atlantic Time Zone|
|11:35, 20 August 2021 AST |
12:35, 20 August 2021 ADT
|Observance of DST|
|DST is observed in parts of this time zone.|
The Atlantic Time Zone is a geographical region that keeps standard time—called Atlantic Standard Time (AST)—by subtracting four hours from Coordinated Universal Time (UTC), resulting in UTC−04:00. During part of the year, some portions of the zone observe daylight saving time, referred to as Atlantic Daylight Time (ADT), by moving their clocks forward one hour to result in UTC−03:00. The clock time in this zone is based on the mean solar time of the 60th meridian west of the Greenwich Observatory.
In Canada, the provinces of New Brunswick,Nova Scotia, and Prince Edward Island are in this zone, though legally they calculate time specifically as an offset of four hours from Greenwich Mean Time (GMT–4) rather than from UTC. Small portions of Quebec (eastern Côte-Nord and the Magdalen Islands) also observe Atlantic Time. Officially, the entirety of Newfoundland and Labrador observes Newfoundland Standard Time, but in practice Atlantic Time is used in most of Labrador.
No portion of the continental United States currently uses Atlantic Time, although it is used by the territories of Puerto Rico and the U.S. Virgin Islands. In the 2010s, several U.S. states considered legislation to move from the Eastern Time Zone to Atlantic Standard Time. Any changes must be approved by the United States Department of Transportation and the United States Congress before taking legal effect.
The National Hurricane Center's official advisories typically report AST and UTC when tracking storms in the Caribbean that threaten the U.S., which may confuse the mainland public not familiar with the time zone designation.
All six of the New England states in the northeastern U.S., currently in the Eastern Time Zone (with daylight saving time), have considered legislation to shift to UTC−04:00, equivalent to Atlantic Standard Time (with no observance of daylight saving time) or Eastern Daylight Time. Virtually all of this region is west of the theoretical western border of the zone at 67.5°W; only a small portion of Maine lies east of that meridian. A Massachusetts commission concluded in 2017 that the benefits of changing to Atlantic Standard Time year-round would outweigh the disadvantages, provided that a majority of northeastern states made the same change.In May 2017, the Maine Senate approved a change to AST, on the condition that there would be a referendum, and that Massachusetts and New Hampshire decided to make the same switch. Also in 2017, the New Hampshire House of Representatives approved a bill in favor of a regional change, but this was voted down by the state's Senate. Similar bills have been put forward in Connecticut, Rhode Island, and Vermont.
In 2018, Florida enacted into law the "Sunshine Protection Act", under which the state would observe daylight saving time year-round. Most of the state would permanently keep Eastern Daylight Time, which is equivalent to Atlantic Standard Time; the state's panhandle region would move to year-round Central Daylight Time / Eastern Standard Time.However, the change cannot take effect until it is passed into federal law by the United States Congress.
A time zone is an area that 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.
The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean Islands, and part of the Eastern Pacific Ocean.
The Eastern Time Zone (ET) is a time zone encompassing part or all of 23 states in the eastern part of the United States, parts of eastern Canada, the state of Quintana Roo in Mexico, Panama and Colombia, mainland Ecuador, Peru, and a small portion of westernmost Brazil in South America, along with certain Caribbean and Atlantic islands.
The Mountain Time Zone of North America keeps time by subtracting seven hours from Coordinated Universal Time (UTC) when standard time (UTC−07:00) is in effect, and by subtracting six hours during daylight saving time (UTC−06:00). The clock time in this zone is based on the mean solar time at the 105th meridian west of the Greenwich Observatory. In the United States, the exact specification for the location of time zones and the dividing lines between zones is set forth in the Code of Federal Regulations at 49 CFR 71.
The Hawaii–Aleutian Time Zone observes Hawaii–Aleutian Standard Time (HST) by subtracting ten hours from Coordinated Universal Time (UTC−10:00). The clock time in this zone is based on the mean solar time of the 150th meridian west of the Greenwich Observatory.
Time in the United States, by law, is divided into nine standard time zones covering the states, territories and other US possessions, with most of the United States 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. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) ; and the United States Naval Observatory (USNO). The clocks run by these services are kept synchronized with each other as well as with those of other international timekeeping organizations.
Moscow Time is the time zone for the city of Moscow, Russia, and most of western Russia, including Saint Petersburg. It is the second-westernmost of the eleven time zones of Russia. It has been set to UTC+03:00 without DST since 26 October 2014; before that date it had been set to UTC+04:00 year-round on 27 March 2011.
The Newfoundland Time Zone (NT) is a geographic region that keeps time by subtracting 3+1⁄2 hours from Coordinated Universal Time (UTC) during standard time, resulting in UTC−03:30; or subtracting 2+1⁄2 hours during daylight saving time. The clock time in this zone is based on the mean solar time of the meridian 52 degrees and 30 arcminutes west of the Greenwich Observatory. It is observed solely in the Canadian province of Newfoundland and Labrador.
UTC−04:00 is an identifier for a time offset from UTC of −04:00. It is observed in the Eastern Time Zone during the warm months of daylight saving time, as Eastern Daylight Time. The Atlantic Time Zone observes it during standard time . It is observed all year in the Eastern Caribbean and several South American countries.
UTC+03:00 is an identifier for a time offset from UTC of +03:00. In areas using this time offset, the time is three hours later than the Coordinated Universal Time (UTC). Following the ISO 8601 standard, a time with this offset would be written as, for example, 2019-02-08T23:36:06+03:00.
Australia uses three main time zones: Australian Western Standard Time, Australian Central Standard Time, and Australian Eastern Standard Time. Time is regulated by the individual state governments, some of which observe daylight saving time (DST). Australia's external territories observe different time zones.
Time in Brazil is calculated using standard time, and the country is divided into four standard time zones: UTC−02:00, UTC−03:00, UTC−04:00 and UTC−05:00.
Canada is divided into six time zones, based on proposals by Scottish Canadian railway engineer Sandford Fleming, who pioneered the use of the 24-hour clock, the world's time zone system, and a standard prime meridian. Most of Canada operates on standard time from the first Sunday in November to the second Sunday in March and daylight saving time the rest of the year.
The Chamorro Time Zone, formerly the Guam Time Zone, is a United States time zone which observes standard time ten hours ahead of Coordinated Universal Time (UTC+10:00). The clock time in this zone is based on the mean solar time of the 150th meridian east of the Greenwich Observatory.
Mexico uses four main time zones since February 2015. Most of the country observes Daylight Saving Time (DST).
Daylight saving time in the United States is 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. Most areas of the United States and Canada observe daylight saving time (DST), the exceptions being Arizona, Hawaii, and the overseas territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the United States Virgin Islands. The Uniform Time Act of 1966 established the system of uniform daylight saving time throughout the US.
Daylight saving time (DST) is currently observed in nine of ten provinces and two of three territories in Canada, but with exceptions in several provinces and Nunavut. Most of the province of Saskatchewan, despite geographically being in the Mountain Time Zone, observes year-round Central Standard Time (CST). In 2020, the territory of Yukon abandoned seasonal time change to permanently observe year-round Mountain Standard Time (MST). Under the Canadian Constitution, laws related to timekeeping are a provincial or territorial matter.
Daylight saving time in the Americas is the arrangement in the Americas by which clocks are advanced by one hour in spring and moved back in autumn, to make the most of seasonal daylight. The practice is widespread in North America, with most of Canada, Mexico, and the United States of America participating, but much less so in South America.
Time in Maine, as in all US states, is regulated by the United States Department of Transportation. All of Maine is in the Eastern Time Zone (ET) and observes daylight saving time (DST).
Time in Massachusetts, as in all US states, is regulated by the United States Department of Transportation. Massachusetts is in the Eastern Time Zone (ET) and observes daylight saving time (DST).
In Vermont, Democrat Rep. Samuel Young this year has submitted legislation that would establish year-round Eastern daylight saving time.
|Time zone||Hours from UTC: Standard time||Hours from UTC: Daylight saving time|
|Hawaii–Aleutian (in Hawaii)||−10||−10|
|Hawaii–Aleutian (parts of Alaska)||−10||−9|
|Pacific (parts of Alaska)||−8||−8|
|Pacific (other states/provinces)||−8||−7|
|Mountain (Arizona, Sonora, Yukon, and Northeastern British Columbia only)||−7||−7|
|Mountain (other states/provinces)||−7||−6|
|Central (other states/provinces)||−6||−5|
|Eastern (parts of Nunavut, Ontario, and the Caribbean)||−5||−5|
|Eastern (other states/provinces)||−5||−4|
|Atlantic (Natashquan River)||−4||−4|
|Atlantic (other states/provinces)||−4||−3|
| Saint Pierre and Miquelon |
and most of Greenland