On Thursday, March 10th, 2011 at 06:24:53h +0000, David Kaye explained:

Mexico continues to observe the last Sunday of March to last Sunday of
October schedule as we used to

Except, according to Wikipedia

As of December 2009, the Mexican Congress gave permission to these
ten northern border cities to synchronize their time to that of
their US counterparts:

Matamoros, Tamaulipas
Reynosa, Tamaulipas
Nuevo Laredo, Tamaulipas
Anahuac, Nuevo Leon
Acuna, Coahuila
Piedras Negras, Coahuila
Ojinaga, Chihuahua
Juarez, Chihuahua
Mexicali, Baja California
Tijuana, Baja California

And I read somewhere that unsurprisingly the Mexican Stock Exchange
observes daylight savings time during the same periods as the rest
of North America.