If you set your machine to the DST timezone for your political unit, then the displayed time will automatically jump back and forth on the correct dates, as lon

If you set your machine to the DST timezone for your political unit, then the displayed time will automatically jump back and forth on the correct dates, as long as your time database is reasonably up-to-date; you don't need to manually change from non-DST to DST & back. The non-DST timezones are for those who are lucky enough to live in political units which tell DST to get bent, and just stay on real time all year long. DST delenda est.