On 2020-12-29 19:08, Brian Park wrote: > > The core of why it "just works" seems be in the interpretation > of the "2:00 transition to US Rule", and the fact that "2:00" is Wall-time, > not S-time or U-time: Then why does your code work for the transition at 1991 Mar 31 2:00s in Kaliningrad? Michael Deckers.