when does the time change to central time
Central Time Zone In those areas of the Canadian and American time zones that observe DST, beginning in 2007, the local time changes at 02:00 local standard time to 03:00 local daylight time on the second Sunday in March and returns at 02:00 local daylight time to 01:00 local standard time on the first Sunday in November. Mexico decided not to go along with this change and observes their horario de verano from the first Sunday in April to the last Sunday in October. In December 2009, the Mexican Congress allowed ten border cities, eight of which are in states that observe Central Time, to adopt the U.S. daylight time schedule effective in 2010.
Time Earth is split up into a number of time zones. Most time zones are exactly one hour apart, and by convention compute their local time as an offset from GMT. For example, time zones at sea are based on GMT. In many locations (but not at sea) these offsets vary twice yearly due to daylight saving time transitions.