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 National Research Council (NRC) maintains Canada's official time through the use of atomic clocks. The official time is specified in legislation passed by the individual provinces. In Quebec it is based on coordinated universal time. The other provinces use mean solar time. The NRC provides both coordinated universal time and mean solar time in its signals. It makes time servers available for direct synchronization with computers. The Canadian Broadcasting Corporation has aired a daily time signal, the National Research Council Time Signal, since November 5, 1939.
The Government of Canada recommends use of the 24-hour clock (e.g. 05:06), which is widely used in contexts such as transportation schedules, parking meters, and data transmission. Speakers of Canadian French predominantly use this system, but most users of Canadian English use the 12-hour clock in everyday speech (e.g. 5:06 a.m.), even when reading from a 24-hour display, similar to the use of the 24-hour clock in the United Kingdom.
Pacific Standard Time (PST) GMT-08:00 and Pacific Daylight Time (PDT) GMT-07:00:
Pacific Daylight Time (PDT) GMT-07:00 year-round:
Mountain Standard Time (MST) GMT-07:00 and Mountain Daylight Time (MDT) GMT-06:00:
Mountain Standard Time (MST) GMT-07:00 year-round:
Central Standard Time (CST) GMT-06:00 and Central Daylight Time CDT GMT-05:00:
Central Standard Time (CST) GMT-06:00 year-round:
Eastern Standard Time (EST) GMT-05:00 and Eastern Daylight Time (EDT) GMT-04:00:
Eastern Standard Time (EST) GMT-05:00 year-round:
Atlantic Standard Time (AST) GMT-04:00 and Atlantic Daylight Time (ADT) GMT-03:00:
Atlantic Standard Time (AST) UTC-04:00 year-round:
Newfoundland Standard Time (NST) GMT-03:30 and Newfoundland Daylight Time (NDT) GMT-02:30:
Four Canadian cities, by local ordinance, used daylight saving time in 1916. Brandon, Manitoba,adopted it on April 17. It was followed by Winnipeg on April 23, Halifax on April 30, and Hamilton, Ontario, on June 4.Port Arthur, Ontario, was the first place in the world to introduce it, on July 1, 1908.
Daylight saving time is currently observed in all ten provinces and three territories but with several exceptions in several provinces and Nunavut, including most of Saskatchewan, which despite geographically being in the Mountain Time Zone observes year-round CST. Under the Constitution of Canada, laws related to timekeeping are a purely provincial matter. In practice, since the late 1960s DST across Canada has been closely or completely synchronized with its observance in the United States to promote consistent economic and social interaction. When the United States extended DST in 1987 to the first Sunday in April, all DST-observing Canadian provinces followed suit to mimic the change.
In 2019, the legislature of British Columbia began the process of eliminating the practice of observing daylight saving time in the province. On October 31, 2019, the government introduced Bill 40 in the legislature, which would define "Pacific Time" as "7 hours behind Coordinated Universal Time (UTC)". In a press release, the provincial government stated an intention to maintain alignment of clock time with Washington, Oregon, California, and Yukon. The move follows a consultation earlier in 2019, in which the province received over 223,000 responses, 93% of which said they would prefer year-round DST as compared to the status quo of changing the clocks twice a year. The premier of British Columbia discussed the issue with Yukon premier Sandy Silver, who said in October that he needs more consultation with Yukon stakeholders, and with Alberta and Alaska.
The latest United States change (Energy Policy Act of 2005), adding parts of March and November starting in 2007, was adopted by the various provinces and territories on the following dates:
|C.c.*||Coordinates*||TZ*||Comments*||UTC offset||UTC offset DST||Notes|
|CA||+4734-05243||America/St_Johns||Newfoundland Time, including SE Labrador||-03:30||-02:30|
|CA||+4439-06336||America/Halifax||Atlantic Time - Nova Scotia (most places), PEI||-04:00||-03:00||Plus Îles-de-la-Madeleine and Listuguj Mi?gmaq First Nation in Quebec.|
|CA||+4612-05957||America/Glace_Bay||Atlantic Time - Nova Scotia - places that did not observe DST 1966-1971||-04:00||-03:00||Likely includes all of Cape Breton Island.|
|CA||+4606-06447||America/Moncton||Atlantic Time - New Brunswick||-04:00||-03:00||Like America/Halifax, except DST time change happens at midnight rather than 2:00 a.m.|
|CA||+5320-06025||America/Goose_Bay||Atlantic Time - Labrador - most locations||-04:00||-03:00||Places that used Newfoundland Time until 1966.|
|CA||+5125-05707||America/Blanc-Sablon||Atlantic Standard Time - Quebec - Lower North Shore||-04:00||-04:00||East of 63rd meridian west.|
|CA||+4531-07334||America/Montreal||Eastern Time - Quebec - most locations||-05:00||-04:00||Redirects to America/Toronto.|
|CA||+4339-07923||America/Toronto||Eastern Time - Ontario & Quebec - most locations||-05:00||-04:00||Legally, its western border is 90th meridian west, but there are many de facto exceptions.|
|CA||+4901-08816||America/Nipigon||Eastern Time - Ontario & Quebec - places that did not observe DST 1967-1973||-05:00||-04:00||Places using Eastern time that did not observe DST 1967-1973.|
|CA||+4823-08915||America/Thunder_Bay||Eastern Time - Thunder Bay, Ontario||-05:00||-04:00||Places in Eastern Time that skipped DST in 1973.|
|CA||+6344-06828||America/Iqaluit||Eastern Time - east Nunavut - most locations||-05:00||-04:00|
|CA||+6608-06544||America/Pangnirtung||Eastern Time - Pangnirtung, Nunavut||-05:00||-04:00||Places that switched from Atlantic Time to Eastern Time in 1995.|
|CA||+744144-0944945||America/Resolute||Central Time - Resolute, Nunavut||-06:00||-05:00||Places in Central Time that skipped DST in 2007.|
|CA||+484531-0913718||America/Atikokan||Eastern Standard Time - Atikokan, Ontario and Southampton I, Nunavut||-05:00||-05:00||Legally CST/CDT, but in practice observes EST year-round.|
|CA||+624900-0920459||America/Rankin_Inlet||Central Time - central Nunavut||-06:00||-05:00|
|CA||+4953-09709||America/Winnipeg||Central Time - Manitoba & west Ontario||-06:00||-05:00||Includes Big Trout Lake and Denare Beach, though by law they should be in America/Toronto and America/Regina, respectively.|
|CA||+4843-09434||America/Rainy_River||Central Time - Rainy River & Fort Frances, Ontario||-06:00||-05:00||Places using Central time that did not observe DST 1967-1973.|
|CA||+5024-10439||America/Regina||Central Standard Time - Saskatchewan - most locations||-06:00||-06:00|
|CA||+5017-10750||America/Swift_Current||Central Standard Time - Saskatchewan - midwest||-06:00||-06:00||Western Saskatchewan towns that used Mountain Time until 1972.|
|CA||+5333-11328||America/Edmonton||Mountain Time - Alberta, east British Columbia & west Saskatchewan||-07:00||-06:00|
|CA||+690650-1050310||America/Cambridge_Bay||Mountain Time - west Nunavut||-07:00||-06:00|
|CA||+6227-11421||America/Yellowknife||Mountain Time - central Northwest Territories||-07:00||-06:00||East of 120th meridian west.|
|CA||+682059-1334300||America/Inuvik||Mountain Time - west Northwest Territories||-07:00||-06:00||West of 120th meridian west.|
|CA||+4906-11631||America/Creston||Mountain Standard Time - Creston, British Columbia||-07:00||-07:00||Places in Pacific Time that have not used DST since the database cuttoff date (1970).|
|CA||+5946-12014||America/Dawson_Creek||Mountain Standard Time - Dawson Creek & Fort Saint John, British Columbia||-07:00||-07:00||Places in Pacific Time that stopped using DST in 1973.|
|CA||+4916-12307||America/Vancouver||Pacific Time - west British Columbia||-08:00||-07:00|
|CA||+6043-13503||America/Whitehorse||Pacific Time - south Yukon||-08:00||-07:00||East of 138th meridian west.|
|CA||+6404-13925||America/Dawson||Pacific Time - north Yukon||-08:00||-07:00||West of 138th meridian west.|