I'm a bit confused regarding the output from zdump for the new America/Ojinaga zone. Here's the output for 2022: America/Ojinaga Sun Mar 13 08:59:59 2022 UT = Sun Mar 13 01:59:59 2022 MST isdst=0 gmtoff=-25200 America/Ojinaga Sun Mar 13 09:00:00 2022 UT = Sun Mar 13 03:00:00 2022 MDT isdst=1 gmtoff=-21600 America/Ojinaga Sun Oct 30 07:59:59 2022 UT = Sun Oct 30 01:59:59 2022 MDT isdst=1 gmtoff=-21600 America/Ojinaga Sun Oct 30 08:00:00 2022 UT = Sun Oct 30 03:00:00 2022 CDT isdst=1 gmtoff=-18000 America/Ojinaga Sun Nov 6 06:59:59 2022 UT = Sun Nov 6 01:59:59 2022 CDT isdst=1 gmtoff=-18000 America/Ojinaga Sun Nov 6 07:00:00 2022 UT = Sun Nov 6 01:00:00 2022 CST isdst=0 gmtoff=-21600 Note that there's no November 30 event. But based on the zone's definition I'd expect to see these events: Oct 30 - change to _CST_ Nov 30 - No change, I guess, since the change to the US rules on Nov 30 doesn't actually change the offset or isdst flag. But maybe I'm misunderstanding how to interpret the zone file definition? Cheers, Dave Rolsky http://blog.urth.org https://github.com/autarch