A good example is the northern panhandle of Idaho. It should be in the Mountain time zone but given it's proximity to the Spokane, WA area it is in the Pacific time zone.
Time zones are meaningless in aviation and marine. Ships and planes all use Universal Time Coordinated (UTC) or Zulu time. So it is the same time everywhere in the world. We vote for party time too!!
Time Got a smart phone? Ask it. They usually have a clock with capabilities to set different spots of the world. Should be five hours difference I think. Works great!!
So it will change three days before we get there. Two hours difference for us but we will hopefully get there and still have sun.
Don.t worry,, the first they do on final approach into Cancun, is the tell you the correct time and weather Enjoy