Thank you for accepting my suggestions. My understanding of the transition at 1997-10-26 02:00 is also what you described.

David

On Sunday, August 18, 2024 at 11:24:57 PM EDT, Paul Eggert <eggert@cs.ucla.edu> wrote:


Thanks for that detailed study of Mexican decrees. I transcribed your
results into TZDB format and installed the attached proposed patch into
the developmental repository on GitHub.

One thing came up when I was reading your comments. You wrote "Quintana

Roo changed to UTC-6 on 4 January 1983 at 0:00, and again to UTC-5 on 26

October 1997 at 2:00." In the attached patch, I'm taking this to mean
that because America/Cancun observed Mexican-style DST in 1996 and 1997,
its 1997-10-26 02:00 "transition" was from CDT (-05, or -06 with DST) to
EST (-05), i.e., civil-time clocks didn't actually jump that day. If
this understanding is incorrect please let us know.

Thanks again.