The xtd::time_zone_info::transition_time object returned by the xtd::time_zone_info::transition_time::daylight_transition_start property defines either a fixed-date rule or a floating-date rule for the transition to daylight saving time. A fixed-date rule provides the month, day, and time of day on which the transition occurs. A floating-date rule provides the month, the week, the day of the week, and the time of day on which the transition occurs.