Hi, I made some calculations ( conversions between GMT and Europe/Lisbon ) in the websites referred at http://www.twinsun.com/tz/tz-link.htm, like "The World Clock" or "Time Zone Converter .
I looked for some difficult examples. But here they are: In the 25th September 1977, in Europe/Lisbon, the difference to GMT changed to 0h at 1 A.M. If I calculate the time offset in the above websites, I get that this null difference is assumed not at 1 A.M., but from 0h A.M. forward. In the 30th September of 1979, in the same location, the difference ( before of one hour ) is 0h, regarding GMT, at 2 A.M. According to their program, again, this change begins either at 1 A.M. or 0h AM, of that day - not at 2 A.M., at it was suposed to be. Is this an error in their calculations? Or is the TZ Database wrong? Kind regards, Rui Miguel Fernandes Porto - Portugal
