Atlantic Time Zone

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Atlantic Time Zone
UTC offset
AST UTC−4:00
ADT UTC−3:00
Current time (Refresh the clock.)
ADT 9:14 pm on May 23, 2018
AST 8:14 pm on May 23, 2018
Observance of DST
DST is observed in certain regions of this time zone between the 2nd Sunday in March and the 1st Sunday in November.
DST began Mar 11, 2018
DST ends Nov 4, 2018

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-4; during part of the year some parts of it observe daylight saving time by instead subtracting only three hours (UTC-3). 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,[1] Nova Scotia,[2] and Prince Edward Island reckon time specifically as an offset of 4 hours from Greenwich Mean time (GMT-4). Small portions of Quebec (eastern Côte-Nord and the Magdalen Islands) are also part of the Atlantic Standard Time Zone. Officially, the entirety of Newfoundland and Labrador observes Newfoundland Standard Time,[3] but in practice most of Labrador uses the Atlantic Standard Time Zone.

No portion of the continental United States currently uses Atlantic Time; however the territories of Puerto Rico and the U.S. Virgin Islands do use Atlantic Standard Time. A number of New England states are considering a regional year-round change to Atlantic Standard Time, even though only a small portion of Maine lies to the east of the 67.5°W theoretical extent of this zone. Florida is also considering a similar change; in both cases any changes would need to be approved by the United States Department of Transportation and the United States Congress.

Those portions of the Atlantic Time Zone that participate in daylight saving time do so as Atlantic Daylight Time (ADT), which has one hour added to make it only three hours behind GMT (UTC-3).

Areas covered[edit]

U.S. states considering changing to Atlantic Time[edit]

A Massachusetts commission concluded in 2017 that the benefits of changing to Atlantic Standard Time would outweigh the disadvantages, provided that a majority of north-eastern states made the same change;[5] in May 2017, the Maine Senate approved a change to Atlantic Time, on the condition there would be a referendum, and that Massachusetts and New Hampshire decided to make the same switch.[6] Also in 2017, the New Hampshire House of Representatives approved a bill in favour of a regional change, but this was voted down by the state's Senate.[7]. Similar bills have been put forward in Connecticut and Rhode Island.[6]

In Florida, two bills were approved in January 2018 by House and Senate committees, to move most of the state permanently to Atlantic Standard Time (with the panhandle moving to year-round Eastern Standard Time).[8]

See also[edit]


  1. ^ "CHAPTER T-6 – Time Definition Act" (PDF). Archived from the original (PDF) on 2008-12-07. Retrieved 2012-09-11. 
  2. ^ "Time Definition Act". Archived from the original on 5 June 2008. Retrieved 2008-06-02. 
  3. ^ "RSNL1990 CHAPTER S-23 – STANDARD TIME ACT". Retrieved 2007-11-16. 
  4. ^ [1]
  5. ^ "Commission: Massachusetts Should Change Time Zones, But Not On Its Own". November 1, 2017. Retrieved March 15, 2018. 
  6. ^ a b "Maine Considers Atlantic Standard Time". Retrieved March 15, 2018. 
  7. ^ "Senate votes down push to switch N.H.'s time zone". May 11, 2017. Retrieved March 15, 2018. 
  8. ^

External links[edit]