Paul Gilmartin via tz <tz@iana.org> wrote:
Doesn't TAI use the Gregorian calendar, so 2017:01:01t00:00:00 TAI is 2016:12:31t23:59:23 UTC. That's just a timezone convention -- the date may differ among various timezones.
Not "just", I'm afraid. When a timezone changes offset (e.g. to or from DST) the periods with different offsets follow directly one after the other. So, to avoid ambiguity when the clocks go back, you need to write down both the time and the offset. But when DTAI changed from 36 to 37 there was a one second gap, the leap second 2016-12-31 23:59:60. Instead of including a DTAI offset in the time, we disambiguate with a special :60 second. Tony. -- f.anthony.n.finch <dot@dotat.at> https://dotat.at/ Cape Wrath to Rattray Head including Orkney: East or northeast 4 or 5, occasionally 6 at first. Slight or moderate. Showers. Good.