1908
adopted
Port Arthur, Ontario, now part of Thunder Bay, is cited as the first known place to use modern DST.
DST timeline
Daylight saving time in Canada has 3 recorded changes on record, spanning 1908–2007. The earliest documented event is the adoption in 1908: Port Arthur, Ontario, now part of Thunder Bay, is cited as the first known place to use modern DST. The most recent is the modification in 2007: Most Canadian DST regions aligned with the expanded US March-to-November schedule. As of the latest data, Canada is shown as "Regional" in our daylight saving tracker, which is the practical takeaway for anyone scheduling calls, travel, or deliveries against this region today.
Port Arthur, Ontario, now part of Thunder Bay, is cited as the first known place to use modern DST.
Each entry records a distinct daylight saving milestone for Canada. An adoption marks the year clocks first began shifting; an abolition marks the year the country stopped changing them and settled on a single year-round offset; a modification covers changes to the start or end dates, the size of the shift, or which regions take part; and a reform vote records a legislative or parliamentary decision that may not yet be in force. Years reflect when the change took effect, not when it was announced, so a 2019 vote and a later effective date can both appear.
Daylight saving rules change more often than most people expect, and historical offsets are exactly the detail that breaks date math for past timestamps, travel records, and historical scheduling. If you only need today’s behaviour for Canada, the current-status link above is the fastest answer; if you are reconstructing a past date or comparing several countries, the full timeline and the linked sources below give you the authoritative record.