How many time zones are there in Canada?

Time zones are regions with a uniform standard time for social, commercial, and legal purposes. They are used for ease of communication and simplicity. Regions in close communication such as subdivisions in countries keep the same time. Higher latitude countries use the daylight saving time to manipulate clock time. Abbreviations are often used to represent the different time zones (e.g. CST, WST, and EST), but they are not part of ISO 8601.

There are six time zones in Canada: Pacific Time, Mountain Time, Central Time, Eastern Time, Atlantic Time, and Newfoundland Time. Pacific Time includes the Northwest Territories, Yukon, and almost all of British Columbia. The zone is 3 hours behind Eastern Time, 1 hour behind Mountain Time, and 1 hour ahead of Alaska Time. Mountain Time includes portions of northeastern and southeastern British Columbia, most of the Northwest Territories and Nunavut, parts of Saskatchewan, and all of Alberta. It is 6 hours behind GMT (Greenwich Mean Time) during daylight saving time (early autumn, summer, and spring) and 7 hours behind during the shortest days of winter and autumn. Major metropolitan areas in the Mountain Time Zone are Calgary and Edmonton, Alberta and Cranbrook, British Columbia.

The Central Time Zone includes the western parts of Nunavut (parts of Qikiqtaaluk region and Kivalliq Region), Manitoba, parts of Ontario, and most of Saskatchewan. The Central Time zone is 6 hours behind GMT during the shortest days of winter and autumn and 5 hours behind during daylight saving time. One exception is Lloydminster, a town found on the provincial border between Saskatchewan and Alberta, which observes DST and Mountain Time.

The Eastern Time Zone includes east-central Nunavut (most of Baffin Islands and Ellesmere and part of Melville Peninsula), Quebec (excluding the Magdalen Islands and eastern Cote-Nord), and Ontario (including Atikokan but excluding areas to the west of Thunder Bay). The Eastern Time Zone is 5 hours behind GMT in autumn and winter and 4 hours behind during daylight saving time. In the Eastern Time Zone, DST or daylight saving time ends around November 4.

The Atlantic Standard Time Zone includes Prince Edward Island, Nova Scotia, New Brunswick, Labrador (except the southeastern tip), and Quebec (east of the 63W longitude and the Natashquan River). AST is 4 hours behind the Greenwich Mean Time. Major metropolitan areas in the Atlantic Standard Time Zone are Moncton, Charlottetown, and Cape Breton Regional Municipality.

The Newfoundland Standard Time Zone is 2 hours behind during daylight saving time and 3 behind the Greenwich Mean Time. Newfoundland Time is used by Newfoundland and Labrador only. By legislation, Newfoundland and Labrador is in NT, but it is observed only in some south-eastern Labrador communities and on Newfoundland and its offshore islands. The province observes daylight saving time. Newfoundland is half an hour ahead of Prince Edward Island, Nova Scotia, and New Brunswick, 1 hour ahead of Central Canada, and hour behind Saint-Pierre and Miquelon.