<Tr> <Td_colspan="2"> DST is observed in parts of this time zone . </Td> </Tr> <P> 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 . </P> <P> 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 . </P> <P> 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 . A number of New England states are considering a regional change to Atlantic Standard Time year - round (with no observance of daylight saving 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 in the process of enacting a similar change; in both cases any changes will need to be approved by the United States Department of Transportation and the United States Congress . </P>

Where does the atlantic time zone start in canada
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