On 2022-12-09 15:11, Tim Parenti via tz wrote:

On Fri, 9 Dec 2022 at 16:46, Nikos (Nikolaos) Papadakos, PhD wrote:

...

Our customer is a major airline in Mexico and they tell me the time should America/Ojinaga should be the same as America/Denver. It is our understanding that the recent changes split time zone observances along Chihuahua's northern border.  According to that split, from 2022-11-30, Ojinaga is like America/Chicago, while Ciudad Juárez is like America/Denver. III. Para el Estado de Baja California, así como para los municipios de Janos, Ascensión, Juárez, Praxedis G. Guerrero y Guadalupe, del Estado de Chihuahua, acorde a sus correlativos a su franja fronteriza, se aplica el meridiano 105 grados al oeste de Greenwich." While the above describes that the municipio of Juárez (including its municipal seat, Ciudad Juárez) observes a standard time of UTC-7, which is like America/Denver, the section immediately prior reads: II. Para los municipios de Coyame del Sotol, Ojinaga y Manuel Benavides, del Estado de Chihuahua, acorde a sus correlativos a su franja fronteriza, se aplica el meridiano 90 grados al oeste de Greenwich; …meaning that the city and municipio of Ojinaga follow UTC-6, which is like America/Chicago. A new zone, America/Ciudad_Juarez, was split off from America/Ojinaga in 2022g to allow for these differences in timekeeping. Since this zone did not exist prior to 2022g, those in the western portions of Chihuahua's border region (including Juárez) will need to switch to it, as the time in and around Juárez and Chihuahua's northwest no longer matches the time in Ojinaga and Chihuahua's northeast. Nor the time in Chihuahua's interior which is on CST like Ojinaga. The airline can check the IATA SSIM Schedule Time Zones for CUU/MMC Chihuahua and CJS/MMCS Ciudad Juarez to confirm the changes (Ojinaga has no airport).

-- Take care. Thanks, Brian Inglis Calgary, Alberta, Canada La perfection est atteinte Perfection is achieved non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut -- Antoine de Saint-Exupéry