In Canada, daylight saving time is the practice of turning clocks ahead one hour on the second Sunday in March and back one hour on the first Sunday in November. Canada has six standard time zones that may be abbreviated as PST (pacific standard time), MST (mountain standard time), etc. However, during the daylight saving period between March and November, they may be abbreviated as PDT, MDT, etc. The boundaries of the standard time zones are not necessarily the same as those of the corresponding daylight saving time zones. For example, the mountain time zone includes a portion of northeastern British Columbia in the summer, but not during the winter (see maps below). Boundaries shift because some municipalities choose not to participate in daylight saving time. Saskatchewan follows central standard time year-round.

(courtesy National Research Council Canada) (courtesy National Resource Council Canada) PreviousNext

Why Does Daylight Saving Time Exist?

The Canadian government introduced daylight saving time in 1918 as a measure for increasing production during the First World War. Similar legislation had been passed in Germany and Britain. The idea was that during months when the sun stays visible for longer, a pre-breakfast hour of daylight could be saved for use after supper. Countries did this by turning the clocks ahead by one hour in the spring (to start the day earlier) and back by one hour in the fall.

History of Daylight Saving Time in Canada

Federal government regulation of daylight saving time lapsed with the end of the First World War, but resumed during the Second World War. During the Second World War, Canada used daylight saving time all year round, as did the United States. Most countries used some sort of daylight saving time during the war. Great Britain, for example, put the clocks ahead one hour during the winter months and two hours during the summer.

Municipalities in Canada came to regulate DST to reduce the confusion present when different businesses on the same street used different times. The provinces became involved, passing different sorts of time legislation. Since 1987, official time zones and DST have been regulated by the provincial, territorial and municipal governments.

From 1988 until 2006, for the parts of Canada that use DST, clocks followed the North American pattern of moving one hour forward on the first Sunday in April and one hour back on the last Sunday of October. However, since March 2007, the standard North American period for DST has been from the second Sunday of March to the first Sunday of November. The United States introduced this shift in 2005 when President George W. Bush signed legislation changing the annual beginning and end of DST. The new schedule was introduced to save energy, the rationale being that people would not need to have their lights on as early in the evening. Despite predictions of reduced consumption, data indicating energy savings has been elusive.

Canadian provinces and territories, like nations around the world, followed the American plan to change the scope of DST. It was essential to do so for trade, travel and communications, because the US is Canada’s chief trading partner.