How many time zones does Canada span?

Canada spans six time zones from coast to coast. From east to west: Newfoundland Time (UTC minus 3:30) covers most of Newfoundland and the southeast coast of Labrador, Atlantic Time (UTC minus 4) covers the rest of the Atlantic provinces and most of Labrador, Eastern Time (UTC minus 5) covers most of Quebec and Ontario, Central Time (UTC minus 6) covers western Ontario, Manitoba, eastern Saskatchewan, and Nunavut west of 102 degrees west, Mountain Time (UTC minus 7) covers most of Saskatchewan, Alberta, northeastern British Columbia, and the Northwest Territories, and Pacific Time (UTC minus 8) covers most of British Columbia and Yukon.

Newfoundland Time is unique in North America for its 30-minute offset from neighbouring time zones, set by Newfoundland's Standard Time Act of 1935 while the country was still a Dominion separate from Canada. Despite occasional proposals to align with Atlantic Time, the half-hour offset has remained in place since Newfoundland and Labrador joined Confederation in 1949. Saskatchewan is unique among provinces for not observing daylight saving time year-round, remaining on Central Standard Time (which is equivalent to Mountain Daylight Time during summer).

Canadian railways were the original driver of standardised time zones. Sir Sandford Fleming, a Scottish-Canadian engineer who became Chief Engineer of the Canadian Pacific Railway in 1872, developed the proposal for worldwide standard time zones to address the chaos of railway scheduling. He presented the proposal at the International Meridian Conference in Washington, DC in October 1884, where the world adopted Greenwich Mean Time and the 24 hour-wide zones still used today. Fleming is sometimes called 'the father of standard time'.

Daylight saving time observance varies. Most of Canada follows the federal Time Act and observes daylight saving time from the second Sunday in March to the first Sunday in November (matching the United States). Most of Saskatchewan and parts of British Columbia (the Peace River regional districts), Quebec (some Lower North Shore communities), Nunavut (the Kugluktuk hamlet), and Ontario (some Thunder Bay area) opt out. Yukon ended daylight saving time on November 1, 2020 and now stays on year-round Yukon Standard Time (UTC minus 7), the same as Mountain Standard Time. Ontario passed legislation in 2020 (Bill 214) authorising a permanent move to year-round Eastern Daylight Time, contingent on Quebec and New York making the same change.