This reminds me of a SNAFU when I lived in Las Vegas. I was taking seaplane flying lessons in Bullhead City, AZ. I was unaware at the time that AZ had any deviation from standard time protocol. I was also shamefully unaware that it wasn't in the same time zone as NV (I had only moved out there a month earlier). On the first day of instruction, I was two hours late because of the time zone and DST difference. On the following weekend, I showed up an hour early because the switch from DST/ST occurred during that week.