Also, Microsoft is moving ahead with DST for Quintana Roo in an upcoming Hotfix for Windows. http://blogs.technet.com/b/dst2007/archive/2015/02/06/upcoming-windows-dst-u... To: eggert@cs.ucla.edu; tz@iana.org From: mj1856@hotmail.com Date: Thu, 5 Feb 2015 20:51:45 -0800 Subject: Re: [tz] Fwd: Quintana Roo change to EST? The CENAM belongs to the Economic Secretary. My understanding is that this is the official department that would set the policy - similar to NIST in the US. From: Paul Eggert Sent: ‎2/‎5/‎2015 4:29 PM To: Matt Johnson; Time Zone Database Subject: Re: [tz] Fwd: Quintana Roo change to EST? There were conflicting reports about this back when Mexico was considering doing the change in October of this year. As I understand it, Mexico decided to move the change up to this month, and to stay on EST all year. For a brief summary please see: http://www.timeanddate.com/news/time/mexico-quintana-roo-time-zone.html It could well be that this is wrong. There's at least one English-language source saying that it hasn't been decided whether Quintana Roo will observe DST: http://www.blogsouthwest.com/who-moved-my-queso-cancun-changes-time-zone/ and perhaps we'll need a further update once this becomes decided or sufficiently clear. That being said, my (admittedly limited) understanding of QRoo politics suggests that they won't observe DST this year. That CENAM web page is reasonably generic and perhaps its author didn't think about (or want to think about) predicting exactly what will happen in April.