Ihor Radchenko <yanta...@posteo.net> writes:
> https://www.youtube.com/watch?v=-5wpm-gesOY gives various examples. > To summarize: > > 1. Time (YYYY-MM-DD HH:MM) not continuous and may change arbitrarily at > certain times a year or in future or in the past: > - DST transitions are not stable and change from year to year > according to strange rules that may involve Julian dates or > counting weekdays > - DST transition rules may change over time > - The new year day itself is not necessarily fixed (England > - Julian/Gregorian transitions happened at different times in > different countries > Note that as a result "time when it happened" has different rules than "future time when it is scheduled". There are lots of other times that are scheduled as "future local time, subject to changing DST rules". This is particularly tricky for repeating times for regularly scheduled events. > 5. Leap seconds! 23:59:59 -> 23:59:60 -> 00:00:00, according to > astronomical Earth observations > Fortunately, the most recent vote reached majority for eliminating leap seconds, hopefully within 8 years. -- Robert Horn rjh...@alum.mit.edu
