[IanPBann]

The comment you replied to is correct based on what you said - if you start in a state in permanent summer time, travel south to a state in permanent winter time, keep travelling south to a state in permanent summer time, and so on, you will be going back and forth by an hour repeatedly.

Hypothetically, if you start just north of Sittard and east of the German/Netherlands border (in Germany), and travel in a straight line, almost due south to Geneva in Switzerland, you could, depending on what time member states choose to permanently adopt, potentially go from German summertime, to Dutch wintertime, to Belgian summertime, to Luxembourgish wintertime, to French summertime, to Swiss wintertime, all in under 350 miles and with not much deviation in longitude.

[sergioisidoro]

Ah! you are correct. I thought the author was referring to the possibility of a country south of another being 1h ahead/behind depending if they do the yearly switch or not.

But in this case we go to the general problem of choosing of timezones. You have plenty of cases of south borders with different timezones (ie. without moving in longitude you still switch zones).

It's a matter of country size, not to mention that it is a matter of economic interest to keep the same timezone as neighbouring countries. I would assume the scenario you mentioned to be quite unlikely.

[soneil]

If Belgium and the Netherlands don't agree on a timezone, you could probably do that in the space of half a mile at https://en.wikipedia.org/wiki/Baarle-Nassau