A note on time zones

This is the first time I've driven into a new time zone. The island nature of the UK means you either fly or sit on a ferry or go by train, but you don't just drive across some imaginary line that says "now change your watch". We are in possibly the most confusing part of the USA. Utah is on Mountain Time (an hour ahead of California and Nevada). Arizona is also on Mountain Time but unlike Utah, Arizona doesn't practice daylight savings so now Arizona is in the same time zone as California. Except the Navajo Nation (a large chunk of northern Arizona starting a few miles down the road) does do daylight savings. Depending on where my phone thinks it is, and it keeps changing its mind, it's either 9ish or 10ish and I'm not sure it really matters.