North America generally follows the same procedure, going by local time in each zone, each time zone switching at 02:00 LST (local standard time) to 03:00 LDT (local daylight time) on the first Sunday in April,* and again from 02:00 LDT to 01:00 LST on the last Sunday in October*.
* In 2007, the starting and ending dates for DST will change in the United States and parts of Canada (see below).
The Canadian province of Newfoundland and Labrador is an exception in that the time changes take place at 00:01 local standard time and 00:01 local daylight time respectively. Also, in 1988, they experimented with Double Daylight Time, when the clocks went ahead by two hours, instead of the usual one hour. Manitoba begins DST at 02:00, but switches back to standard time in October at 03:00.
-
http://en.wikipedia.org/wiki/Daylight_Savings