TimeTraces takes time zones and daylight saving time into account. So, when you change time zones or when daylight saving time comes into effect, your time traces will keep recording the correct start- and end date/time, and thus the correct duration.
When you have switched time zones, the start- and end times will be reported for the current time zone. This means that the start and end time will be adjusted with the time difference between the current time zone and the time zone the time trace was recorded in. When you e.g. worked from 9:00 to 11:00 in the old time zone and consecutively switch to a time zone with a difference of 4 hours, this will be shown as 13:00 to 15:00 in the new time zone.