Several states in the world are going to change their clocks at the end of this month. Unfortunately they don’t do it all at the same time, nor they do the same thing. All of Europe is going to change clock one hour backwards at 01:00 UTC Oct 29th. USA change the same night, but each timezone on its own 02:00. Normally I am six hours from New York, and nine hours from Los Angeles. Starting at 2am Oct 29th CET and for the next six hours I’m gonna be only 5 hours from NY and 8 from LA. From 7am until 10am I’m going to be 6 hours from NY and 8 from LA. After 10am hour relative time difference wiil be the usual one.

China doesn’t have a daylight saving policy, so this is simple. Currently Beijing is 6 hours from Italy but will be 7 after we switch our clock. But much worse happens for countries in the other emisphere. For example Sydney is currently 8 hours away. They are going to switch their clock the same day Oct 29th, but their 2am will happen at 6pm of my Oct 28th and they’re going towards summer, so they will change their clocks one hour forward! Between 6pm and 2am we’re going to be 9 hours behind them, and after 2am we’re going to be 10 hours away! Same twist happens for Rio de Janeiro, but they will change clock on the first Sunday of November. And, by the way, not all of Brazil and Australia observe DST.

I wonder how people who developed the software used to book flights managed all of this mess. They deserve a medal.